My brother, Ben (who is called Makkon), created a map that I took some screenshots of.
It's so detailed that it just goes too slow to be playable, but it shows some pretty decent skill. I just thought you all could give him some useful feedback.
http://static.condemned.com/makkon/cast2/
The download doesn't work right now, forgot to put it on the zip disk. ;)
I'm wondering if he could make use of the eye candy entities to replace some of the repeated architecture with some models or bspmodels, or if that would just slow it down even more...
Anyway, he's got a bunch more maps that I intend to screenshot and put up there. Most are very detailed (he'd be great for Q3 or UT2003, or even doom3 when it's out; but quake runs too slow). Hopefully he can get some real good advice from y'all.