Would one of you guys be willing to try to get a rev. 29 BIOS?
I believe that in the BIOS version, the 4 is pretty much in all cards, the .17 is for NV17 chips (GF4 MXs) and the .25 is for NV25 chipst (GF4 Tis), I'm not sure what the next .00 field is, and I'm not sure what the last .00 field is. But the second to last field, where mine says .29 and yours are .28 and .24, might be the revision...
If you wouldn't mind trying, see if you can find a .29 video BIOS for your card. That would at least narrow it down -- if .28 doesn't work and .29 does, then that's the fix, I guess... Kind of annoying, but if there are BIOS bugs, then there are BIOS bugs.