Are you adverse to a tow dolly (probably yes, if a trailer is a no-go)? Then rent a car that can go on the tow dolly.
As for a dingy renting business, maybe. It would be a specialized car rental business. Might buy a couple used Jeep Liberty to start and setup with base plate towbar, brake, and lights. ReadyBrute comes to mind. Would have to provide drop/riser receiver adapters, etc. as well. As you comment, insurance might be a problem.
Vince and Susan
2011 Tiffin Phaeton 40QTH (Cummins ISC/Freightliner)
Flat towing a modified 2005 Jeep (Rubicon Wrangler)
Previously a 2002 Fleetwood Pace Arrow 37A and a 1995 Safari Trek 2830.