Hello
There is one I know of thats pretty decent, but I cant remember the name, sorry. I can tell you how to get there though. From anywhere downtown along market, grab a muni N train (not bus) in the tunnel and head out past west portal. You may have to get off at 19th and Ocean, the shop is on Ocean somewhere between 15th and 19th or thereabouts. Ocean is a nice little neighborhood in that area, theres a bunch of shops along that strip and one is a hobby shop with a very good (for here) plane section.
If you have a car available, about 35 miles south, 45 minutes on 101, in Mt View there is San Antonio hobby shop. Their url is
http://www.sahobby.com/. Easy to get to, right off the freeway about a mile or two, and lotsa stuff.
Erix