Other than that I can suggest something like the spaceship map for Killing Floor that came out at christmas. Make use of some of the more 'modern' looking props rather than hay piles and wood piles etc.
i've wanted to make a space-themed map, so i +1 this. it'd fit with the spytech tf2 theme, and would be really fun to make. a few ideas, in case you'd be interested:
- either a spaceship or lunar/asteroid base drifting through space (I actually started a ph_asteroid but never put too much time into it)
- lowered gravity, like the KF map
- airlocks to go into space (just to get around - add damage triggers so you can't hide out there)
if you need help lemme know!