I've been tinkering with the Hammer world editor for source as a diversion between bouts of video editing. So far my efforts have resulted in this really lame deathmatch map. Obviously it needs a lot of work and will include flight control rooms and stuff. They're there already... I just need to make doors. The scale is screwed up as I was guestimating but I now have a better sense of the scale the editor creates. The textures need help and the geometry need to be made more interesting. Also the space needs populating with scale fighter models and ordinance.
You can follow the progress in this thread... and, as you can see from these screenshots, he's already gone on to add a pretty impressive staircase!