It'd be neat to create a spray-coating that instantly grows epitaxial SiO2 layers as you spray it on a conductor in a clean-room environment, lending to "spray-on" silicon solar cells.
I'd like to do something like this for an electric-powered scooter (around 250-350W electric motor and a 32Vdc LION battery). Just make the scooter and spray the stuff on as if a spraypaint or something.
I can drive around all day without recharging the darn thing! :) :) :)