I'm running 64-bit RHEL 6.3 with kernel-ml version 3.4.5 with a GT 640 (three monitor support from single card). I was using 302.17 just fine and loved being able to configure my monitors from the normal display settings application, since two of my monitiors are rotated while the third isn't. I tried upgrading to 304.22 but my mouse cursor disappeared Strangely, it showed up in gdm but not after logging in. Also, the two non-primary monitors were just black, even though I could move my mouse into that area. I was able to deduce my cursor location by dragging along my desktop.
Any ideas? Seems like an obvious bug. I used a fresh xorg.conf from nvidia-xconfig too with no entries for my other monitors, since it now seems to be configured externally from xorg.conf.