FPS RPG's are flooding the market at press time, so don't even bother to mention them.
Fallout 3, Bioshock, S.T.A.L.K.E.R....
It's not even out that long, and the market is being saturated.
As for a FPS RTS, I think the closest we've gotten to the genre would be Tom Clancy's EndWar, where you...