Well, I'm just across the bay from San Francisco... Mine is 9' x 8' and was partitioned out of an existing building. Details at http://grahampatterson.home.comcast..../darkroom.html It's a standard wet side/dry side arrangement. It is just big enough to run 11x14 prints in a dev, stop, fix, rinse sequence without using a tray stacker.
This is my first permanent darkroom. I'd like a little more space, but compared to various temporary arrangements it is bliss.