Check out Jason Giacchino's homepage article detailing 8 extremely modified quads. Are any of these a good idea?

 

I'm kinda liking the quadski!

 

"Environmentalists love to cause ATV riders grief, but savvy riders living next door to Al Gore’s sprawling mansion have developed a quad that targets many of the “tree-hugger’s” greatest complaints: Among these loud exhaust pipes, pollution, and well, an engine. The bad news is that out-of-shape riders reported being sorely disappointed in the vehicle’s short range of operation and lack of cup-holders. Additionally, rare cases of methane pollution due to overexertion have been reported."

Scooter?

Too funny!