Actually, you CAN tow a Jeep on a dolly. All you have to do is get under it and remove the rear drive shaft. The same applies to a 4X2 Jeep.
If you are lucky enough to find an older Jeep that has had the Warn hub kit installed on the rear axle, you can just unlock the rear hubs.
Towing a 4X4 Jeep 4 down is so easy. I used an inexpensive Reese fixed-arm tow bar on Jeeps for years. You can find them at Walmart for less than $200!