If you were upfront about your plans, I don' t see why a homebirth midwife wouldn't just take you on for prenatal care. Seems reasonable to me! The midwives I know do hourly consulting as well as general gynecological care. I can't imagine it would be hard to find someone willing to do a few months of prenatal care.
Also, the homebirth midwives I am familiar with have all taken women very late in pregnancy. After all, just because you're switching care-providers doesn't make you high risk, and you can't very well help that you'll be moving, so why wouldn't they? Again, seems reasonable!