Torklift Central has developed an ECO-Stealth tow hitch for the Leaf that hides neatly below the vehicle's rear bumper and handles either a 1.25" or 2" receiver. Since the Leaf isn't officially sanctioned for towing, any damage caused from this activity could cause Nissan to void the car's warranty; so it's probably not advisable to try dragging the Queen Mary to the lake. Besides, towing a heavy load would seriously degrade the vehicle's battery range.
However, the torque delivered by the Leaf's electric motors makes it more than capable of light towing duties. Many Leaf owners are likely also to be users of kayaks, bikes, or other gear, and a trailer hitch provides a range of additional options for bringing outdoor toys to the outdoors.
Torklift Central also offers the ECO-Stealth hitch for the 2012 Toyota Prius and 2012 Chevy Volt, and even plans to offer a version for the diminutive 2012 Mitsubishi i.