Oh yah Rocket Arena would be a nice type mod - love the zero respawn options (if I'm thinking of the right mod).
I'd also like to see an OSP JK 2.
Those guys know balance - imo.
Another Q3 mod that has a really funny voting system is Threewave.
You battle it out over gametypes, and then people jump through Alice and Wonderland type doorways to choose maps.