build your own
http://cgi.ebay.com/ebaymotors/trail-gr ... enameZWDVW
this guy thinks his truck is worth something. it's using 4 ski-doo snowmobile skids (suspension rails + Idler wheels) with some goofy $#!& welded to the rims.
that wouldn't hold up to abuse, and it wouldn't hold up to a powerful motor, because those skids are just aluminum and about 1"x2" and not that thick for the whole measurement.
but, for what it's worth, he did get a decent design out of it.