(Disclaimer: I know this has been around for a while but we have a LOT of new members)
The mod that takes the two hit games and combines them, Unreal Annihilation, will finally be released (first beta) on April 20th! Originally in development for UT(99), UA has gone through a lot (I've been eagerly following it's progress, I LOVED TA )
Noy only does it allow the player to control thier army from the 'God' perspective seen in all RTS games, but you can also possess a unit to take the enemy army head on!
Multiple players on the same team can be both in the God view or both posessing units, requiring teamwork and coordination to defeat your opponents.
(btw I'm in no way affiliated with the UA team. I just like the idea muchly)
Check it out: Unreal Annihilation