I wondered the same thing; having come up from Central America and hanging around the Magic Castle in Hollywood for several days. Truth is, I didn't find too much. There is a Calumet photo, and there are Sammy's in L.A. and Santa Ana, but nothing huge that I've seen. There are a couple of larger places that seem to do grip equipment and peripheral stuff, but not too much on cameras.
I think what you're looking for may be in Burbank, but I haven't been.
