Maybe in Alaska, but no well-known rental places in the lower 48, that's for sure.
sabconsulting only explored the tip of the iceberg with regards to the liabilities and pitfalls of renting just a TC, and when you're talking about a TC and a truck, a Class C motor home will cover the renter's needs 99.9% of the time, and is infinitely more marketable.
Just think, almost every 1/2 ton on the market needs to have airbags or some other helper spring setup to handle ANY TC at all. How many of your truck-driving friends, who do NOT camp, have airbags on their Tundra/F150/Silverado/RAM 1500 "just in case" they want to rent a TC someday?
Think about it for yourself... Would you want to go to the expense of installing airbags or helper springs for what is possibly a one-time event?
How many guys own 3/4 or 1 ton trucks as daily drivers, and don't use them for ANYTHING? Not for towing, not for work, not for hauling a TC... They just like riding around getting 12MPG and beating their spines to pieces... NOT.
Putting 10-ply tires on half ton trucks since aught-four.