Michael Gordon (http://www.michael-gordon.com) is doing a weekend LF workshop next March at Joshua Tree. I'm signed up (been trying to find a date that worked for me for a few years)- he's an excellent photographer and teacher. It's listed at Julia Dean Photo Workshops (www.juliadean.com), which is L.A.-based. I think Michael also does 1-on1 workshops, and he's based in Long Beach.
In my own quest for retirement photo courses (twenty since 2003) I found at least the University of Akron, OH wanted you to take Photo 1 and 2 before taking a LF course. I had been shooting 35mm for 40 years, but still got a lot out of the courses. Half way through the LF course I was so taken by the idea I bought my first LF camera (Linhof Technikardan) to use in completing the course even though Calumet studio cameras were provided.