How's it going with Natural Selection 2?
They are already taking preorders! However they don't have mac or linux under supported operating systems. Which is understandable as they haven't begun porting it yet. It would be really great if the linux client would be ready by the time of the release!
But they seem really open to the idea of a linux/mac client as I pointed out in my post in the previous thread with links
Sid Meier's Alpha Centauri (and Alien Crossfire) are on my wishlist (IIRC an AC port existed once, but don't know what happened to it).
PS. Maybe it was already discussed (didn't read the other thread), but Freespace2 engine has already been ported and works perfectly well on linux; you only need to purchase the Windows version from GOG and get the engine from the "Hard Light Productions" site.