I have seen limited selections of Guittard chips at Cost Plus World Market. Also, Nicole's Gourmet Foods in South Pasadena sells several varieties of interesting chocolate couverture. Give them a call.
Nicole's Gourmet Foods
921 Meridian Ave, South Pasadena, CA 91030
I don't know about the Coverture part but recently heard folks mention finding Guittard at Trader Joes and Target, of all places. (Wonder about World Market also.) I have not personally looked for it any of those places.
I looked for a stores link at the Website but didn't find one, however looks like they ship:
does it have to be Guittard?
Surfas in Culver City has a huge selection of Callebaut, which i personally think is superior...but chocolate is a funny thing, we all have our preferences/loyalties :)
ETA: you might also try contacting one of the local places that rents or sells chocolate fountains, as they typically use couverture...
(come to think of it, the La Jolla location of Whole Foods had a chocolate fountain when i lived there, perhaps one of the newer LA area stores does...?)