In the right area of the country I could see a decent market for renting Jeep Wranglers and Rubicons as the rental options for that type of car tend to be fairly limited.

That said, off-road vehicles will tend to be taken off-road and beat up a bit. It's unclear whether the insurance covered by Turo covers the vehicle being used off-road etc. Of course, if someone is running this as a business, they can presumably get their own commercial insurance.