Homebirth with twins?
Oh, sorry, I meant to link you to it. Here it is ;)
When are you due?
We also have a thread for people who are pregnant with twins right now.
I had a wonderful homebirth with our di-di twins, on the East Coast so I can't help with a midwife. But what I've learned from the process is that you do have to be a careful shopper. Out of sheer dumb luck I ended up with a wonderful midwife, the backup of my original less-competant midwife who had to leave halfway into labor. The backup midwife was experienced from serving the Amish, and had caught something like 40 sets of twins before mine, and came equipped with some helpful equipment. Her skill was light-years beyond the "cowboy" midwife who accepted me originally but probably shouldn't have. Not that we were ever in danger with the first midwife, it's just the skills, manner, and little tricks experience had taught the back-up midwife meant the difference between a blissful HB and a transfer to the hospital.
In your shoes, I'd try and get in touch with some great American midwives and ask who they might recommend in California.
Also, at least in my area homebirth transfer is an ugly and hostile business. If that's true in yours too, I'd establish parallel care with an OB (might just not share HB plans). The OB will probably be alarmist and occasionally annoying, but will at least have a record of you and you babes in case you have to transfer, you could do it seamlessly with an "Oopps, labor just came so fast" comment and you might get better care.
Very best wishes!
We found (in California) that midwives, for home or for birth center, wouldn't deliver twins because of legal restrictions (though there were always rumors that we could get to one by driving a few hours...). We wound up with a very natural birth friendly OB who is the backup OB for the homebirth midwives in the area. I would suggest talking to people and asking whether they know anyone who might be able/willing to help you. It may be a long chain, but people in the birth community generally know each other.
Rinap, sounds like you are in the same area of CA we lived in when I birthed the twins.
Gena's advice is very wise. In CA, from what I could find, you'll likely find cowboy but not the experience that allows confidence.
I went for a HB but ended up transferring (non-emergent) to a supportive OB. If I did it again I'd go directly with the OB but labor at home for a while first.