Those are all amazing vehicles. I played a bit with water cooled solar cells, I found that the hard part wasn't the cooling but to be able to draw that much current from a single cell, the attachment points for the wiring typically really weren't up to the job and having multiple attachment points became a necessity. You also need a pretty beefy pump and radiator to get rid of the excess heat, though I guess in a vehicle you would use an active system with a fan.

What I don't understand about the Viking 29 article is how an 8 KW generator is going to power a 75 KW motor, is there something I'm missing?