After 2 c-sections, I had a homebirth last July. I however, kept my dual care until I reached 37 weeks (at which point I told them I was having a homebirth and they dropped me), but here is why - because if anything happened earlier, like premature labor or some other complication, my midwife would have had to turn me over to doctors anyhow and a homebirth wasn't possible - so I figured it would be best if I had regular doctors to go to if something happened. At 37 weeks, I knew that at anytime after that if I went into labor, the midwife could attend me. Also, I figured if something happened and I needed to transfer, the hospital would have access to a full record of pre-natal care since I had received doctor care to term.
Fortunately, there was no need and I had a wonderful HBA2C. I was very happy to follow up with the doctor practice to let them know how wonderful my homebirth was, and I certainly hope it made an impression on them so that they are supportive of other VBA2Cs (they were pretty hestitant to "let me have a trial of labor").