I just watched this clip on youtube http://www.youtube.com/watch?v=3Z7s6_OdwHc a friend sent me about G-boarding. For those who don't know G-boards are gas powered skateboards that are made for all terrain. Its relatively new technology so it costs $500 now but in a year or less the price should drop to more average consumer level. If you don't have the patience and want to splurge now, I highly recommend it.
The "Wheelman," G-board has a 43cc or 49cc 2 stroke engine, can hold up to 90kg and has a max speed of 35km/h. For more info on the Wheelman and a bunch of other cool bikes and quads go to www.shukeda.com I ride anything with a board so I'm going to try on the first chance I get...check it out.