Yes, there is a low power station in San Diego with KSEX-LP on channel 42 and there is another one listed as KZTC-LP.
I'm not sure that either of these stations are really on the air. When you go to KZTC's FCC registration page and try to call the phone number, it goes to an independent builder. Also, their website is really non-existent (sandiego7.com).
http://en.wikipedia.org/wiki/KZTC-LP