I think that the support is equally as important as the choice of machine. Parajet and Vince White at Air Conception UK both offer this in bucketfuls. Also be careful with frame size as in my experience, a lot of these units seem better for someone of 5ft 8in or more (which is what I am). I once snapped the end off a stationary propeller landing with one of the bigger machines. Of course, this all depends on the geometry of the particular machine. As Steve said above, I doubt you would go wrong with either the AC or Maverick. Just avoid anything that hangs low on your back.
Regards