Considered this at one point, actually. If I were to do this, would I need to swap my PC video card out with a Mac-compatible one first, or would OSX run in some kind of basic video mode (no hardware acceleration) so that I could do firmware upgrades?
Hmmm. Good question. My guess would be that it would not boot at all with the PC video card. If you have one of the lower end video cards for the Mac (or could obtain one) you could leave it in one of the other slots and switch to it when necessary.