When I was surfing around today I came across a Unicycle tank from a 1933 issue of Popular Science on Boing Boing, a real working motorcycle where the rider sits insider the only wheel, a hoop that is about 7 feet tall. In Star Wars Episode III, the droid enemy General Greivous rides a wheelbike that looks almost exactly like this contraption designed over 70 years ago. It makes you wonder if George Lucas really reads old science mags; it would be cool if he did.
Check this: Grievous' wheelbike features "mechanical legs that could be used in an alternate walking mode," while Popular Science's older version includes
steel-tube crutches that project ahead on either side like medieval lances. As the tank rushes upon a trench or obstruction, the operator will drop the tubes so they dig into the earth and the whole machine will vault through the air to the other side.
Somehow not surprisingly, more than one version of this bike is out there, including the brightly colored Wheelsurf (via Penguin Perspectives). As you can see in the pics and video included at the site, the Wheelsurf does not sport the legs or guns. The vehicle is described this way:
Imagine yourself in a centrifuge. The world is all yours. It is you and gravity forces. You are in the pipeline, the road is like water and you are surfing on it. It is fun, excitement, it is a thrill.
As for me, I'd go for Lucas's wheelbike, but if that doesn't pan out, I'd settle for the version highlighted on Boing Boing, Kerry McLean's Rocket Roadster.