Have a look at this, basically a wheel with rubber lips:
http://www.maxionwheels.com/News/421/MAXION-Flexible-Wheel-with-MICHELIN-ACORUS-Technology.aspx
Probably not useful for racing done on pavement because of the effective loss of sidewall stiffness, but would be great for a DD or perhaps an offroad vehicle. 19"+ models are going to be sold carmakers, no word on when the wheels would be available on the aftermarket.
