About a month ago we saw comments from John Carmack indicating that Linux versions of RAGE and the new DOOM game were up in the air, as the id technical director said: "There are no firm plans for linux ports of the idTech 5 titles, but it certainly isn’t off the table." Now a later email exchange with Mr. Carmack posted to the Ubuntu Forums (thanks Ant and LinuxGames) indicates that the chances they will port their Tech5 titles to Linux are nearing ever-closer to the edge of that table, with a later exchange repeating his thinking that it "probably wouldn't be all that bad to get it running on the nvidia binary drivers, but the chance of it working correctly and acceptably anywhere else would be small." Here's his overview of the situation:

The PC and Mac versions are still OpenGL 2.x.

We are not currently scheduling native linux ports. It isn't out of the question, but I don't think we will be able to justify the work. If there are hundreds of thousands of linux users playing Quake Live when we are done with Rage, that would certainly influence our decision...