A year or so ago I was tinkering with the 87xx-series drivers and the Feisty kernel, and managed to get them working. This morning I ran into a similar problem — no working binary driver for my Geforce 440 Go card, where every attempt to build the module(s) failed.
I found this thread in the NvNews forums that explains the issue — that the driver needs to be patched before it can be compiled against the 2.6.25 kernel. Sounds a lot like what I was doing a year and a half ago.
I made sure I had a compatible kernel by following this page in the Gentoo documentation, then patched and built the driver. The short steps in the post worked perfectly for me. Installing it and applying the changes only took a few minutes, and I have 2200+ fps in glxgears in Crux Linux now. I still have to add
Option "UseDisplayDevice" "DFP"
in the Device section, or I get a blank screen. Then I add my own last step — the
nvidia-xconfig --composite --allow-glx-with-composite --render-accel --add-argb-glx-visuals --no-logo — and everything is wonderful again.
Well, almost everything. I do, of course, have a one-second-long hang attached to my boot while the screen snaps to life (which doesn’t happen with the xf86 nv driver) but screen rendering and general desktop performance are better. You give a little, you get a little, I say.