Hello! There was a thread on this a while ago and the consensus seemed to be that licensed midwives cannot deliver twins at home in California. I think because it's considered high-risk and LM's can only attend low-risk births at home. Perhaps someone else will chime in with some more info.
When interviewing homebirth midwives in Los Angeles, this was one of the questions I asked along with breech, etc. mostly because I was nosy. No one I interviewed did either and both stated that it was outside the standard of care for homebirths. They both said homebirths were a safe and good alternative for low risk women only. They didn't mention if it was a state restriction or not but they did use the same language.
They both said they knew several OBs who were qualified and competent to do vaginal births for both and would actually do them rather than risking the mama out at the last minute but that they felt it was safer to have access to non-homebirth services for both.
Our only free standing birth center told me the other day that they legally cannot do twins at their center. Twins is automatically considered "high risk" and therefore loses its low-risk status with the birth center. I know this does not help you. You might be able to find some not CNM midwives who might take on twins. The problem is going to be finding someone with experience with twins. Otherwise, you're probable better off doing it unassisted if there are no problems with the pregnancy. I would research and research and research some more birthing at home with twins and twin pregnancy so you are prepared for the fear tactics and for the realistic concerns.