Renting a Tow Vehicle

Hi Friends, there are lots of threads on renting a TrailManor, but I've got a need to rent a tow vehicle to take this baby packin in the hills.

Background: I've got a 2616 that I pull to camping establishments within a 100 mile radius of home in the flatlands of the midwest. For these trips I'm using our 2008 Honda Odyssey with tow package, brake controller, and load leveling hitch. But this summer I would like to head to Glacier National Park where we'll have more hill climbing and decent that our van can handle.

Objective: I need to find a SUV for our family of 5 that has some legroom and storage space adequate for a week long trip.

Options Considered:
1) None of the major rental companies seem to allow towing. Even if I can find a vehicle like a Yukon or Suburban at a rental agency that could tow it, I need to know how I can quickly tell, ( while shopping for the right color ), if the vehicle is wired for me to hook up my brake controller. Furthermore, if the unit available when I go to pick it up does not have a receiver hitch I'll have an additional hassle.

2) The local Chevy dealer did not seem interested in renting out a vehicle.

3) I called our local RV dealer and they were unaware of any local shops that rent "exotics" that might be able to tow.

4) I've also considered buying a used vehicle at the start of the summer, and selling it at the end. But this is fraught with risk (gas prices are likely to make it harder to sell at the end of the season) and sales tax would guarantee a baseline cost.

Thoughts, or other creative options to consider?