Don't read the following if you don't want to have the premise of Assassin's Creed spoiled. http://ps3.ign.com/articles/750/750957p1.html Spoiler Still not a lot known, and depending on how Ubisoft was/is going to set this up, it may not really be much of a spoiler. Pretty interesting twist. I read something like this a while back though...actually, one of the first trailers for the game might have alluded to this now that I think about it.
I seem to remember an article in GameInformer when AC was on the cover that made an oblique reference to your spoiler. Nothing as detailed as yours, just a general reference to the possibility.
Hmm...could be very interesting if they don't #*$& it up royally, which seems possible with this kind of twist.