We had a group of really nice Jeeps pass us while doing Sevenmile Rim on the last trip. We identified one to be a rental 4-door JK and I would have been happy to wheel that thing. It was really well setup and was something like $300 per day which would add up, but for a day or two on a vacation wouldn't be a bad way to go.
I'm not that desperate to run Moab that I would do it in a rental. Taking my truck and running what I brung is a big part of it for me.