I would look at Jeeps because there are a number of them that can be flat-towed without a lot of modifications or fancy oil recirculating systems. All I have to do on mine is hook up the brake assist and take the transmission out of gear using a small button on the shifter assembly.
2004 Tiffin Allegro 27.5 ft. P32 18,000 lb GVW. 8.1 liter. Workhorse chassis built May 2002. 21,000 miles. 2012 Jeep Liberty Toad. RVi2 brake unit.