Or possibly charge a capacitor in the same sense? Impractical to an extent, but it would eliminate the need for a battery...I wonder if you could run the output from a piezo through say a 1:2 home-rolled transfomer and swap current for a higher voltage? Might be possible to get a generic (ie., cheap) piezo to work better in a high mix hybrid.
Well maybe not that dramatic, but whats stopping someone from taking it large scale and making some crazy arcs? (besides acquiring the material)Throw that big chunk of piezo from the empire state building, when it hits the ground theres one hell of a lightning strike.