apparently the gentleman pictured is the owner of both vehicles, and he's deceased. you can see how one hobby would have fed the other!
his vx was claimed good for 70 mpg (US) on the highway:
notes:
- boat tailed rear bumper (probably also full under tray faired into it, but i'm just guessing)
- rear wheel skirts
- front wheel arch gap fillers
source:
http://wisil.recumbents.com/car_aerodynamics/