http://gas2.org/2009/10/10/bmws-hybrid-trike-gets-120-mpg/

And a Touring Trike

http://spyder.brp.com/en-US/

Interesting! I have to admit, SR has a surprising deficit of one-person car/bike hybrids.

(It also looks a LOT cooler than those stupid smart cars I see everywhere.)

I had noticed that....and if you are running in places that are not ConUrbation, it makes sense to have some of the smaller vehicles

http://www.harveyev.com/bugE/index.shtml
More 1 seater bikes

The trike the OP linked to is actually a two-seater.

EDIT: You can see in the last photo on the page that it has a second seat behind the first.

I would only ride a 3 wheeled bike if I had a physical disability. Bikes are meant to have 2 wheels. You can't grind the pegs the same.

Something else you can do with three wheels... http://www.aptera.com/