The concept of a shaman or idol follower not being bound to a single archetype, but striving to fulfill a broader path and honor different spirits or divine figures at once is indeed quite fascinating, but the canon SR rules for pantheistic shamans look rather dull and uninspiring. Moreover, they do not cover the case of a mystic that does not give equal honor and attention to all spirits and gods of a tradition or pantheon, but instead follows only a small group of them, e.g. multiple different aspects of a patron god, or several different patron totems.

So I’ve concocted the following tentative rule:

Polytheist Shamans

Polytheist shamans honor and follow several different patron totems or idols. They strive to fulfill the mandates from all of their patron spirits, and they enjoy their combined blessings, to a degree. Characters may follow up to four different totems or idols (idol followers may choose five if two archetypes are very similar and both different aspects of the same god). They may receive advantages among those normally offered by their patrons to a single spell category (detection, illusion) or spirit type (forest, storm) or broader category in limited circumstances (all nature spirits in direct sunlight, resisting all damaging spells). Bonus value generally is +2, but may be +1 or +3 for some patrons. Characters may get up to five different totem advantages from their patrons, with a total of +10 advantage dice, combined. Advantages to the same spell or spirit type from different patrons do not add up, and no two advantages may be used at the same time. Once set, a combination of totem advantages cannot be changed until the next sunrise or sunset. Some polytheist magicians can get one additional totem advantage, to a total of +12 bonus dice, at the cost of being unable to change the bonus set till the next sunrise or sunset, whichever comes later. The magician manifests a disadvantage from each totem or idol they have received a bonus from. If the disadvantage is an Attribute prerequisite, the character must fulfill it, or it cannot receive a bonus from that totem/idol. If different totems or idols give disadvantages to the same spell category or spirit type, they may add up, to a maximum of -2. If they inflict the same behavioral compulsion (such as going berserk in combat, or giving up to a vice or temptation), the target number of the roll to avoid or resist the condition is raised by +1, up to a maximum of +2. The shaman must strive its very best to fulfill the ideals of every patron totem or idol, reconciling and integrating them in its behavior. They must pay heed to each of their totems’ ideals and attempt to appease all of them or suffer the loss of their powers from their totems. All patron totems or idols of a shaman must belong to the same magical tradition or pantheon. Patron totems may be similar or quite different in outlook: spirits value both focusing to explore different aspects of an ideal as well as breadth of outlook and dedication to balance and reconcile diverse archetypes. Radically irreconcilable totems or idols should not be chosen as patrons, though. The shamanic lodge must be set up in a place that constitutes a preferred environment for all of the patron totems or idols. The shamanic mask of a polytheist shaman or idol follower always shows elements from each patron. Astral quests of polytheist shamans must involve as many different shamanic metaplanes as they have patrons (to a maximum of four).
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Opinions ? Suggestions ?

Edit: revised according to discussion.

The problem is that you tend to create a character who is too powerful. The idea of having only a single totem/idol/whatever is that it is more balanced for game play. If you really read the pollytheistic stuff, or you are polytheistic in RL what happens is that you may honor many different Gods but there is one with whom you have a psecial ocnnection and from whom you draw strength.

To reply to your last comment, to use the words of another forum "you momma"

When I say polythiests or even pantheists can have several dieties they can relate to, i don't mean someone looks to Odin/Jupitar/Osiris as different forms of the great father image, but rather they Have a particularly strong bond to Thor as the warrior, but may also acknowledge Odin as all father, Sif as fertility and Loki for tirckery and chaos, but it is to Thor he feels the closest bond.

Or allow the shaman to be polytheist but only get the benefits of one diety at a time. The change could be once a day, or require a simple ritual, taking a few minuttes.

"Today I feel like worshipping Thor"

Of course he has to avoid annoying all the dieties, or the one(s) annoyed might withdraw their support.

The Polytheist thus gains in flexibility (different boni), but has a narrower set of "acceptable" actions or might be subject to conflicting demands from his dieties.

Thor might dislike the Polytheists backstabbing assasination, demanding that he face his oponent in a fair fight, while Loki is only too pleased by the sneakiness.

The Polytheists powerlevel should generally be unchanged from a normal Shamans. I dont like stacking the different Totem bonus dice for that reason.

Edit: But generally its a nice and imaginative idea you´ve come up with Wanderer.

Slightly off-topic, I played a Pantheistic Shaman once. Despite being a shaman she was mostly into Chaos Magic (these days she'd probably be a proponent of the UMT) and used lots of Hermetic imagery in her rituals.

More to the point of this discussion she explained the different bonuses she received each moon as being astrological influences on her magic (she was also big on astrology) and she saw the dozen different Idols she followed as the Zodiac's signs.

I think what you're trying to do doesn't really need new rules, if you come up with an interpretation of the present rules which you like (and your GM OKs) then you can have your be pretty much anything.

If you feel that your pantheistic (or politheistic or whatever) shaman should only follow Odin Loki and Thor (for instance) then he only follows those three Idols...

Maybe for polytheist shamans they can simply shift their totemic patron after x amount of time (I like the sunrise/sunset option similar to nature spirits) but they only get the advantages/disadvantages for their specific totem. For example, the European Magic secton of SOTA2064 has a table in it that gives suggestions for the Norse, Celtic, and Greco-Roman pantheons. So if you have a Norse shaman who follows all of the Norse pantheon, you could use that list to provide the totems to follow, call them by their Norse names, and you can switch them after a certain time period. Similar to holding ritual to a war god before a run, a home/hearth god before trying to heal up after said run, praying to a trickster god when you want to try and win big at a casino while cheating, etc.

Dashifen the pantheistic shaman from MitS is already like this except that the time period is fixed at 28 days. When the full moon comes around next time you get to choose what your boni will be for the next (lunar) month. If you choose to say that your Combat spell bonus is due to your praying to Thor for that month that is simply a matter of how you choose to roleplay that particular magician.

What would be interesting is a system wherein a group of deities. spirits, totems, etc. are corporately treated as one "totem" for the purpose of giving bonuses and penalties. I think the best model for this would be the D&D clerical "domains."

It's kind of obvious, but the easiest way to go at this is to simply to have no Totem. No bonus, no disadvantages.

actually...if we study the concepts behind multi-deity worship we should be able to find a headway to a solution.

The switching of the deities or totems doesn't have to be one based in time.
It can be based, more like it was in many historical followings, in events.

A god of war, a god of creation, a god of dead, a god of fruitility, a god of joy, a god of prosperity, a god of health, etc...etc...

Teh way to go would be to identify which totems or deities are classed under what type of events. What events do they most comonly associate with.

Now, rather than limiting the shaman to an exact number of totems, you can simply make a system that says that if Bear is your War totem then you may have combat help from Bear.
If Turtle is your health totem then you may have help with health from Turtle.

The way to regulate would be best suited by saying the following:
A Pantheistic shaman has up to 6 points to use. (hmm, sounds familiar)
Each bonus from any one Totem costs 1 point. (as in, if it reads +2 dice to sorcery. +2 dice to conjuring. then it would be a choice of one or the other bonuses from that advantage rather than getting both of them)
For every 2 points spent, a disadvantage from one of the Totems that they have received a bonus from must be taken.
No two advantages may be used at the same time.

The end result is a shaman with 6 advantages (which is about 4 over the average) and 3 disadvantages (which is about 2 over the average)

They must pay heed to each of their totems ideals and attempt to appease all of them or suffer the loss of their powers from their totems.
(the more you pick from, the harder the upkeep is to keep it that way.)

Thanks to all for the ideas and suggestions. Follwoing your input I've revised my original idea as follows:

Characters may follow up to four different totems or idols (idol followers may choose five if two archetypes are similar and both different aspects of the same god).

They may get advantages among those normally offered by their patrons to a single spell category (detection, illusion) or spirit type (forest, storm) or broader category in limited circumstances (all nature spirits in direct sunlight, resisting all damaging spells). Bonus value generally is +2, but may be +1 or +3 for some patrons. Characters may get up to five different totem advantages from their patrons, with a total of +10 advantage dice, combined.

Advantages to the same spell or spirit type from different patrons do not add up, and no two advantages may be used at the same time.

A combination of totem advantages cannot be changed until the next sunrise or sunset. Some polytheist magicians can get one additional totem advantage, to a total of +12 bonus dice, at the cost of being unable to change the bonus set till the next sunrise or sunset, whichever comes later.

The magician manifests a disadvantage from each totem or idol they have received a bonus from. If the disadvantage is an Attribute prerequisite, the character must fulfill it, or it cannot receive a bonus from that totem/idol.

If different totems or idols give disadvantages to the same spell category or spirit type, they may add up, to a maximum of -2. If they inflict the same behavioral compulsion (such as going berserk in combat, or giving up to a vice or temptation), the target number of the roll to avoid or resist the condition is raised by +1, up to a maximum of +2.