Toad behind a class B?

About to down size from our 30 foot trailer to a class B. I THINK we need a toad. Rig is "rated" to tow 5,000 pounds, but that doesn't mean you want to tow anything that heavy.
I don't want to have to tow a Smart or anything that tiny. Maybe a Ford Focus or Chey Sonic (both under 3,000 lbs).
New rig is on a 3500 Sprinter chassis and diesel power.

Anyone towing a car behind a class B?

Thanks,

Note: My profile is two rigs old...please ignore. I will update it when we take delivery of new unit