This DOOM 3 and
Winex CVS Instruction Page outlines how to get DOOM 3 up and running under
Linux with the help of the WINE not-emulator. The method "requires a lot of work
and a good deal of klugery" in the words of Agrajag, who sent this along, but it
does provide a chance for those with penguin-powered PCs to check out the game
while waiting for the promised official Linux version.
From the number of people on bit torrent, I don't think Activision avoided choice #1. Plus, there are legit people that are using CD spoofing with Doom 3, just to avoid CD swapping, so I guess it's not covering all the virtual CD packages out there.