I recall seeing that one a couple years back in Popular Science. I still have yet to see any in actual production. I will admit it has great potential, it also has some obvious drawbacks. It will be a nightmare to keep clean, if you think brake dust is difficult to get out of the cracks of your "rims" this thing is going to be fun. What about offroad uses, can you imagine how much mud these things will fling if any gets up in there.
Would it really be that hard to keep the technology but put a sidewall on that thing? It doesn't even have to be functional, just something to make it look nicer.