A couple things to add this thread:
1. My tow vehicle insurance coverage will pay for damage done by the vehicle or any trailer in tow (collision). If I want damage coverage for the trailer (comprehensive), it is a dedicated policy that has nothing to do with collision coverage. You may need to pay a supplemental charge if renting a tow vehicle, so the trailer is also covered.
2. Check auto/truck dealerships that have a fleet department. They usually have rental information for their commercial customers when a vehicle needs to be repaired or serviced.
