MovPac

[DavidJohn]

[Easy Rider]

Because people are too lazy to push a skateboard??

[SUPcheat]

Looks like a good 'un for the surf skate potato.

[Bulky]

I'm not really in the market for something like this but they've been around for awhile.  I remember a guy in my neighborhood who had something similar that operated with a wired controller--before you could have made a functional wireless one for a reasonable price.  Used to watch him cruise around with his teen daughter in tandem.

Seems like these are a much more elegant design without the backpack taking up so much of the riding room.

http://boostedboards.com/