On a slightly more serious note, a good playground for developing thses kinds of things might be products for developing countries. Specifically, those parts that are not on grids.

A lot of things you make must be cheap, must have own power source & must be useful enough to (a) justify spending money in a place without much (b) worth the hassle of putting panels on your roof or whatever.

What seems relatively sensible is a solar powered desktop to start with.

That's even more useful to the urban thief. Not only will they know they have a laptop, but they'll know they've got everything they need in a convenient briefcase.

I'm not saying these things aren't a good idea, I'm just saying most people live in highly urbanized areas where leaving stuff like this in the sun will get them stolen. If you want to take a laptop with you on a fishing trip or into cottage country, then this is ideal.