Thanks for the shout-back. Pretty sure the GPU was soldered on there (just wanted to double check) - and I'm not the greatest at board level soldering so I'll shelve that idea.
Have you tried MacPF on your system just yet? Just curious.
Thanks!
VV5
Even if you were handy with the soldering iron you probably couldn't replace it - you'd need a chip that was pin compatible, power compatible, and that operates similarly enough to the existing chip that the logic board would be able to "talk" to it without modification.
I haven't tried MPF yet - I'm probably going to use MLPF instead of MPF; as far as I can tell, MPF is still very buggy even when installing Mountain Lion whereas MLPF can be done stably (if not more time consuming). I just got the Mac the other day, so I have to wait for the C2D to arrive first, which won't be for a few weeks since it's coming from China. On the plus side, it was only $5...