Now I have stayed away from indepth SR4 rules learning. As a SR3 ref, rules tend to get clouded with SR4 at the table which does not make for a smooth game, so forgive me if there some mention of this in the later edition.

Is there a range for sustaining a spell?

I house rule the range as that of a mage's ability to order an elemental before remote service. This is to stop magicains on the other side of world assisting team mates while creating an alibi and to make the run more personal.

As an aside I do the same for dispelling dice for the same reasons and I do not believe a magician should have to see their team mate to stop an otherwise invisible force. After all this is mine to interprete.

So, I know some require line of sight, some dont have a limit and some like me fall in between.

If you place a range limit on sustaining a spell in person, would a metamagic that increases this range seem reasonable?

In SR4, p. 174, it tells us that area effect, sustained spells can be sustained and even moved as long as the area remains in LOS of the spellcaster. So range is LOS. It says nothing about spells that affect individuals. LOS should not matter for these, otherwise any spells the spellcaster puts on himself would disappear as soon as he looks away from his body. That would be kind of silly.

THere is no range by RAW for sustaining. A spirit can sustain any spell from the Astral or its MetaPlane. You can cast a spell on a teammate and then run away to the other side of the planet. But as soon as you goto sleep... poof spell goes bye bye.

~Thank you for the replies. I shall go and ponder the merit of, both practicle and academic, of a metamagic that increases the range of sustaining opposed to the open range sustaining with in the background of magic.

The centerpoint of the affected area must be in Line of Sight to move it; it does not need to be in Line of Sight to sustain it.

OK, that makes sense. It removes some of the contradiction in my mind between area and individual spells. Now, what if the center of the spell is on a character, and she moves?

The center of an Area spell is always a point in space, never anchored to an object or creature the way a Ward is. Thus, if the character moves, they simply are no longer in the center of the spell.