Below, you'll find links to information about towable vehicles. My favorite is the Chevy Malibu. Not all of them are towable but the VERY BEST place to check is the owner's manual in the car. There should be a section on how to tow the vehicle. Many Malibu models are towable with automatic transmissions with very few restricts (stay under 65mph).
The estimated cost to equip a vehicle is upwards of $2500 by the time you add a tow bracket, towbar, braking system and wire the tail lights to duplicate the motorhome's tail lights.
Dinghy Towing pages at Motorhome MagazineDownloadable Dinghy Towing Guides from Motorhome Magazine for several years are available here after you fill out the form.