The Vectrix isn't, but that's a problem of the Vectrix company, not the fuel cells.

That FCHV sounds like driving a bomb... compressed hydrogen... dangerous. It's cool Toyota's already got a hydrogen-based vehicle but the storage of it needs to be improved - you basically need a car that can work off of gas, or hydrogen-combined liquids that are easy to catalyze, let the car propagate using existing gas stations, then hope there's so many out there some stations begin to offer the hydrogen-mixed fuel to take advantage of the market. So it would basically need 2 fuel tanks and catalyze either, which might mean 2 fuel cell stacks - but again those Protonex cells are a good example of cells that can provide all a Prius needs with very little volume and mass consumed.