The last time I saw some largish ones in LA it was at Pasadena Tropical Fish (in Pasadena, a suburb of LA). They were about 8" if I remember. I don't live very near, and haven't been fish scouting there for several months, but they have had them several times in the past when I have visited. Check them carefully, though, if you buy there.
Here's their info:
Pasadena Tropical Fish Inc
(626) 449-4987
2982 E Colorado Blvd # 108
Pasadena, CA 91107
Last time we bought some at this place (nice, healthy fish, tiny store)
Dragon Aquarium
6507 Lankershim Blvd, North Hollywood, CA
(818) 508-9611
I hope this helps. At least you can try to call and find out.

So long, and thanks for all the fish.