Don't know if getting another vehicle is something you'd consider or not, but if so, and If you like owning a hybrid and want to flat tow, check out Ford's hybrids, the Fusion or Cmax hybrid.
They are both flat towable from the factory, and are one of the most simple, easiest to flat toe. No crazy procedures to go through, no need to disconnect battery or any fuses, just throw it in neutral and go. Is IMO a much better hybrid drivetrain design than the Prius, too, as it can run in EV mode all the way up to 80 mph (Prius forces you into gas mode at 35 mph).
We've been flat towing our Fusion for nearly 5 years now, it works great.