GPU emulate CPU cores?

I've been wondering with all the horse power that modern gpus have and stream processing would it be possible to write some software that can run on a gpu and could emulate cpu cores. Wouldn't that be interesting if you could run "virtual" cpu cores on a gpu and use the speed up video encoding or photo editing? Also in CPU limited games things could be accelerated in that way (GTA IV). Like if you have 4870 x2 it could easily afford to emulate 2-4 cpu cores and completely run a game on the card itself and still get great performance! Image pairing a fast dual core with a gtx295 and being able to emulate more cpu cores. Imagine pairing a 8600gs and a pentium 4 and still being able to have descent multitasking performance! Would this be possible?

Not really. X86 is a lot more flexible than any current GPU programming, and is MUCH faster for any single threaded operation.

Not really, since some code just can't be broken down into a sufficient quantity of simpler units. At best, it would emulate something like a 300MHz, 200 core CPU - amazing on well threaded software, but utter crap for single threads.