I have a three point but I think with a 4 point you can leave the motor alone to work on the H- Bar. Also If you want to run the motor dry you can take the H- Bar out cant you??
Plus if you are going with big horsepower you can add one of these quick release ratchets.
http://www.donspumpservice.com/pubhtml/ratchet.htm
It does cost you some room in the back seat.
If I ever have to replace the universal joints, flex plate or ever grease the U joints the motor has to come out with my bell housing.
My two cents,
RandyH