RE. Re. 240V 60Hz...
A while back a device based on piezoelectrics called a Transoner was touted to be the revolutionary component needed to enable matchbox sized laptop power supplies.
I did have a few ideas, seems that the big problem was the tendency for voltage fade as power increases due to self heating of the ceramic, and eventually the heat causes the ceramic to fracture.
A possible fix would be to use magnetostrictive materials such as galfenol (GaFe) plated onto the back surface of the ceramic as a linear winding and driven directly from a tank circuit.
This would help a lot as it was the density difference that caused most of the fracturing issues.