The difference between One-percenters and the rest of us is the price of their Green Machine.
If you're nostalgic about the Green Machine tricycle you had as a kid and you've got $75K burning a hole in your pocket, then check this out: The Lean Mean Green Machine!
At its heart rumbles an air-cooled, 80" cu. Harley-Davidson v-twin Evo--hailed by some as the engine that saved the iconic company--providing 60 horsepower for speeds up to 50 mph. The front wheel is driven by a chain housed in a protective cowling that replicates the toy's frame and, like its predecessor, the cycle is steered by two handheld push/pull levers that control the two rear wheels via a directional linkage. The hand levers include brakes while a foot lever controls its manual 6-speed transmission. Its 8 1/2-gallon fuel tank is built into the frame, hidden from view, providing a range of 400 miles.
http://www.hammacher.com/Product/11894 - via Laughing Squid
I can understand not wanting to go faster than that on this thing. I would probably be terrified to do so. But there's no reason why it shouldn't be able to do 100 MPH with that engine and a six-speed transmission.
I just want a grownup size one. Pedals. Maybe improved wheels, but one that you can still do spin-out sliding skids on.