Gamespot has an article by Mike Verdu (of Electronic Arts LA) where he explains the pitfalls involved in designing the new interface for Tiberium Wars (the new version of the Command & Conquer real time strategy series) and how they were addressed. While targeted at players, it does have some interesting tidbits about the usability of RTS interfaces, and the final interface seems pretty different from the standard collection of buttons on the bottom of a screen which you would expect to find on a RTS game.