Yes, Rage is coming to Linux
According to LinuxGames.com, Rage IS coming to Linux.
Per John Carmack himself:
"There is certainly no plans for a commercially supported linux version of Rage, but there will very likely be a linux executable made available. It isn't running at the moment, but we have had it compiled in the past. Running on additional platforms usually provides some code quality advantages, and it really only takes one interested programmer to make it happen."
I'm sure TTimo's one of the likely candidates and if not, I've half jokingly offered MY services. :D