@Mr. Gweilo 420 I can readily see how one could be designed almost identically to the Nano.
It would have to use a 12v or similar heater/dimmer (120/240v heaters are just not going to happen without a few car batteries and an inverter or something!) and be a decent bit bigger than a Nano to store a preferably pretty serious battery! I think making something Solo sized could work for this purpose
Jimbob: Having diagnosed, repaired, taken apart and reassembled my Nano myself - I can say that modding a v1 Nano to have the removable cord would probably require sending the unit back to Andy unless you are adept with woodworking (to modify the wooden exterior to fit the cord input socket in the unit) and electronics!
I would love to see the inside of one of the new Nanos, I had thought about creating a removable cord mod for my Nano way back before I bought the unit. However I was stuck on how I would manage to fit any of the power input sockets available to me into the unit properly! My complete lack of woodworking skills is a big hinderence here, so I am stoked to see Andy has designed a solution