Fish's moped might be considered, but a debate would have to occur (noting, it does have a gasoline engine). This is a valid vehicle.
The BioMass entry is obviously a joke (or, if not, I will put my pedal bike on too, which is more efficent than the BioMass bike). The 'SAE Mechanical Advantage' is also obviously a joke (but quite well photoshopped!).
The real question is, who said 'You don't have to sacrifice performance for FE'?. Because, the description for SAE Mechanical Advantage states that, and the whole 'vehicle' appears to be a dig at someone on this board - but I can't remember who said that.
Anyway, 'Troll Car' is now the king of the board, and will remain so until all other vehicles in the top ten are 'proper' vehicles.
Or until the Mods delete it (which I am more than happy for), as they will delete the joke cars too