Yeah there aren't many like it. More if you search the endless sphere forums.
The trike by it's self is about $1000 new. I got it used on craigslist last winter for $360. Probably dropped another $1600 or so on electrifying it. (Motor, controller, 8 RC LIPO batteries, a power supply for the $200 RC battery charger, anderson powerpole connectors, wire, etc)
I have a windwrap fairing on the front of it now too, to help keep the cold out during the winter commutes and improve the efficiency. At the Idaho rates of about $.10 per kilowatt hour it runs me about a dime a day to run to work and back. I have over 1000 miles on it already, so in terms of paying for gas in the Pathfinder, it's paying its self off.
Here is a video I shot when I was assembling it.
http://www.youtube.com/watch?v=-vtPrfcZne4&feature=player_embedded