You first need to figure out what sort of vehicle you prefer, e.g. a sedan or SUV, large or small, etc. And also what your coach's tow weight limit is, e.g. 30,, lbs, 5000 lbs, 10,000 etc. Then you can hunt through the Dinghy Towing Guides for vehicles that will suit your wants & needs. Motorhome Magazine (Good Sam) publishes one annually, as does the FMCA (available to FMCA members only).
http://www.motorhome.com/download-dinghy-guides/
Ford's annual Towing Guide also includes info on towing Ford vehicles as dinghies.
Remco Towing has a look-up service on their website that gives the towability status of most any vehicle, and that can be helpful in verifying that what you are considering is indeed towable.
http://www.remcotowing.com/vehicles
If none of those suit, many vehicles can be modified to make them towable (that's Remco's business, for example). It's not inexpensive, though, usually well over $1000.
You can also tow a front drive vehicle on a tow dolly, e.g. one like this:
https://www.mastertow.com/towdollies
It's not as convenient as 4-down towing, but usually less expensive and handles many common vehicles.