Tesla cars strike me as low, wide, with a lot of mass at the very bottom and well distributed. Plus the electric motors give instant full torque, meaning that that they should be a decent tow vehicle from a power standpoint.
I'm sure it kills range, but I doubt anyone is trying it for the long run.
Plenty of regular cars are used to tow in Europe. Following safety and speed laws, I don't see a huge issue. My Saab was rated for 3500lb!