Go see Ryan or Keith at Non Stop Ciclismo in Ventura. Ryan builds, rides and repairs Fixed gear, single speed and flip/flops - as well as any other 9 or 10 speed road bikes. That entire shop is the standard.
I went into Bicycle Bob's (250 Storke Road, Goleta, CA 93117) a few months ago and they mentioned that they hoped to soon have a fixed wheelset for sale. The guy that I spoke to there rode a SS, so I wouldn't count on any fixed gear expertise.
60s Peugeot conversion, 2002 Santa Cruz Heckler, 2007 Bianchi "Everyone has one" Pista, Beat up Beach Cruiser
Also, AS bikes on campus has a few kids working there who ride fixed, they don't really have a selection of anything on hand other than a few cogs, but they can order parts. Plus you can use their tools for free.