It doesn't matter what the DMV tells you, what a CHP officer tells you, or what your buddy the cop says. Pure and simple, if it is in the vehicle code, it is enforcable, if it is not, then you're good to go. I ran my truck every summer with no doors when I live in Cali, and never got busted.
It is required to have 2 mirrors, your rearview and a drivers side mirror is perfectly acceptable.
At worse case, it is a fix-it ticket offense, last I had one, it was $10 bucks and proof of repair at a CHP office.
