I think it actually is possible to do this with todays technology. Stick one of those super slim batteries on one side, a custom chipset on the other, put that little clear solar paneling on the front and back to charge the phone, and voila.
just guessing the price Hmmmmm $50,000 the life of the Rich and Famous..
But it must be very expensive
they can put a big enough battery to run android lol