I'm sure it could handle the forces.. that curved roof is really, really strong. I'd bet you'd be limited to 45-50 mph, and it'd take you a couple minutes to get up to speed. I once got my bug up to 90! State trooper behind me was awfully impressed.
The handling would be amazing, as it's basically a 5th wheel, but even closer to the CoM of the TV. Torque on my '67 1500cc was 106 N*m for an 840 kg car. It could probably tow up to 1000 kg, 2200 lb. Best part is, if it's cold out, you can drive it down a hill, take a lug nut off two of the wheels, and stick em in your boots.