The only 2 that I know about are MMI in Arizona like you've said and also the one in Orlando,Fl. Any others probably aren't worth your money. I live in Orlando,Fl and know a bunch of people who've gone there and who are currently going there. They all really like it and have gotten jobs right out of graduation. You can call the schools and they can set you up with an apartment that you share with room mates. Or you can set up things for yourself. My boyfriend went to the MMI for boats and they've helped him with getting a job literally a week after he graduated. My advice would be to call them ask them to send a brochure. Maybe take a weekend vacation to one of the locations or both and decide.
If you dont want to relocate out of Cali..google and yahoo might give you a good search for schools. Just put motorcycle mechanic.
Best of luck in your search and schooling.