The ergonomics of this are really tricky. I built a 2 string neck-through fretless bass (ok, it was a stick ? )
I love it because I made it myself, but it's really crap to play. Largely because the lack of body means there is nothing stop the bass from falling fretboard down, so you spend a lot of time fighting with your left hand to keep it twisted in the right position. I don't see how they will avoid the same problem. Notice how they're all sitting down in the video.
...and $3995?
