Superannutation has dug up some resumes from former and current Firaxis staffers confirming that the studio is working on a AAA RTS for PC and consoles that uses Unreal Engine. According to Superannutation the game is not a sequel to Pirates, and Civilization Revolution 2 has been canned, but it might be a spiritual successor to Alpha Centauri (fingers crossed!). At any rate we should hear more about what Firaxis have been up to soon.