[Ken Maltby]

As to the Solar Powering Idea, I would put the solar panels on the back of the device.
Then have a case with a transparent, at least to the light frequencies of the panels,
back and a harder front, to protect the screen. That way you could also have a
backpack with such a window and have it charging all the time you are not using it.
Also, what looks like a small solar panel on your windowsill, might not be such a target
for the sticky fingered. Same goes for in your car.

Luck;
Ken

P.S. Of course if you made a slip-on cover with the panels on it, and were it to connect
to the power as it was slid-in ...