QUOTE (DocTaotsu @ May 13 2008, 12:06 PM)

It would have to be a pre-agreed upon theme and I'd have to sit down with my players and say "Look, I'm going all out here, I can do anything to you and you'll just have to adapt. Does that sound like fun?" I wouldn't just plop that into the middle of an adventure for shits and giggles.
This is certainly not something you drop on the group out of the blue.
You tell them up front that you have an oddball story arc you'd like to run and that it might have some major ramifications for their characters, depending on how it plays out. You don't want to give them any details about it because it'd be too easy to spoil it.
After they agree, you can pace it however you want, a couple adventures, a story arc, whatever. At some point you start dropping hints that somethings not quite kosher...
Contacts the PCs haven't called in a while make off-hand comments like...
"Back so soon?"
"Been hittin' the bottle kinda heavy lately, ain't ya?"
"You want another one? I had a hard enough time getting the last one. You need to treat your gear better, man."
"Why were you in such a shitty mood the other day?"
A security video places them somewhere they never visited.
Something the character never bought shows up on their bank account.
What's going on?! Obviously someone is impersonating them. But why? How? What do they have to gain?
Secretly, either the impostors or the PCs are clones. It doesn't really matter because up until the start of the arc, both the clones and the originals are exactly same people (complete with memories and everything). Its only at the start of the arc that things start diverging, because that was when the clones were activated.
Why on Earth would someone clone a bunch of runners? An experiment. Using some pirated cybermantic techniques, a no-name corp (really, its completely off the books) has managed to create a system to retrieve memories, effectively creating whole personas. Why aren't the clones brain dead? Who says brain death always happens? Who's to say it ever does? Or maybe its part of the new cloning process being used in the memory recall process?
The doubles have been running into the same issues as the originals and for the past few (weeks, days) have been
just missing the other group. The PCs need to eventually meet their doubles. Which group is the real deal though? That's for the players to work out.
As to whether or not there's a timer on the clone's lives... I suggest that the real PCs be the ones to come up out top, if anyone does.
And once the adventure is all said and done, its time to figure out who decided to run this little experiment and give them a talking to.
-paws
written stream-of-thought