Paul Tseng does do homebirths. My doula had used him for her homebirth. There's at least one more that I've heard of but I don't know his name! But I had Paul Tseng for my first birth and can recommend him whole-heartedly.
Parentlink also does assist in homebirths. In fact if you go to their website they have a homebirth package. They have twice monthly gatherings for expectant mums you can attend to meet and talk to them about birth options. I really relied on them heavily for info as we moved to Singapore 5 months into my first pregnancy.
http://parentlink.org/pregnant_singapor ... ebirth.htm
I have been considering a homebirth here as well for my second (first was at TMC). I believe a doctor does need to be present, don't think they license midwives to deliver. I think that the other doula company here, 4trimesters, also assists in homebirths if you want (but I have no experience with them).