Have the individual get a small model steam engine, perhaps a
    Cheddar like mine hooked up to one of your little disk drive
    spindle motors to run the pic and a couple other small loads?

Come to think of it, most (all?) steam engines will run off pretty much
any source of high-pressure gas, right?  And there are model airplane
motors that will run off a CO2 cartridge, and even a set of toys on the
market currently that drive a propellar using a (logical) soda bottle
full of compressed air (from a bicycle-style pump. "Air-hogs", I think
they're called.)

BillW