This is more of a question than an actual request, but here goes :
Most of the GPUs Apple provides for the Mac Pro are flashed with EFI-specific ROMs that allow their use under EFI (before legacy support is enabled), but the actual situation varies quite a bit :
X1900XT : EFI ROM (either EFI32 or bytecode) on the card, BIOS ROM within Apple's EFI (loaded when legacy support is needed).
HD2600XT : legacy ROM on the card (so it's no different at all from a PC one), (probably?) EFI ROM within Apple's EFI.
7300GT : fat (legacy + EFI32) ROM on the card.
8800GT : fat (legacy + EFI64) ROM on the card.
Quadros : unknown...
Given that it seems possible to initialize a GPU without using the ROM on it, would it be possible to write an EFI utility that, when launching rEFIt, sets up whatever GPUs are present for non-legacy use ?
This would allow the use of any PC-bound GPU in these categories in a MP, without having to reflash it...