there's an old guy in my parent's neighborhood with one….i tried it out.
it has two "buttons" on the surface of the deck…one in the nose and one in the tail. To go forward you press down on the front button which progressively accelerates faster the harder you push down. The rear button is for the brake.
It's a cool idea, but they are super heavy, and you can REALLY fuck yourself up if you aren't used to it. Pressing the wrong buttons and shit like that lol