If you can't find the detailing products you want in So Cal, then they either don't exist or are based in New Jersey or Florida.
I went to Detailing Depot on my last trip back home and found it to be a great place. Meguiar's, Mothers, Eagle One, and One Grand are all based in So Cal. You can call them and ask for local dealers or go to their websites and do a search.
Most every auto accessory joint in LA carries lots of detailing products. I'm sure you can find lots of stuff at the Pomona swap meet or the Long Beach one. And of course, auto body supply stores carry plenty of the good stuff too.