Have a look at
http://www.gizmag.com/go/3603/1/

or google  tweel

Michelin has something new and completely different which might be of
interest to off roaders in particular, the airless tire.

And while you're at gizmag.com, have a look at the airstream article.
Totally foreign to us westy types but always interesting to note that
"excess knows no limits"!