The files you all need to play with are not Geforce.kext, i know it's part of the files but NVDANV50Hal.kext is the kext you might need to edit hardware id's and see if it gives your fermi cards QE/CI. When Nvidia 8800, 9800, GTS 220, 250 etc they all enable NVDANV50Hal after it gets injected.
I just purchased myself an ATI 5770 overclocked, decided to change brands this time so i cannot test the fermi 470 or 480's.
Even though Geforce.kext has fermi code, it could only be partially implemented?
How i need to edit hardware id's and see if it gives your fermi cards QE/CI