Great suggestions. Aloha Warehouse sells a spectrum of ukuleles and is the only San Francisco store that sells Kamaka, KoAloha and Kanile'a ukuleles. If you go to Aloha Warehouse, let the owner, Edgar, know that you're a serious ukulele player. Tell him what ukulele(s) you have, etc. San Francisco Japantown gets a lot of tourists who want to just to play around, and he worries that they might not know how to handle his higher-end ukes. Edgar is very helpful but even moreso, I think, when you talk story with him about ukes. Sometimes he likes it when people who know me say "hi" to him from me (Mark/mds0725 on UU).
If you get to the East Bay, Music Works in El Cerrito has a small selection of higher-end ukes and the owner is very nice. I bought my first ukulele (a Kala solid mahogany concert) there.