So as you guys may have seen, I'm building the Ghost Down Hill Racer in another one of the threads.
I've also built a hovercraft in middle school using two leaf blowers and a huge tractor tire.
Our hovercraft got about 3mm of lift without a passenger and about 1-2 mm lift with a light middle schooler as a passenger. You're welcome to try to make a cardboard version, but I personally think you'd end up being disappointed.
I'll tell ya, building full scale is a ton of work and it's not easy.
However, I'm putting serious consideration into adding a go-cart engine under the hood of our cart after the Red Bull Competition. It would require a serious financial investment and quite a bit more work, but I think it'd be pretty darn cool to cruise around in your own personal ghost. Any "Gear-Heads" have any input into making it work and how much it'd cost?
Also, I've considered selling the cart on e-bay after the race or after putting an engine in it. How much do you think people would be willing to spend on something like that? Any ideas? Maybe I should make a mini poll.