Somehow, I have the feeling they haven't been released because they don't have the bugs worked out . The flexible wheel assembly looks awfully complicated, and I'd imagine you'd get "flat spots" if you happen to park on anything but a nice, flat surface. Also, the tread pattern looks awfully skimpy.

Wait a minute. I know where I've seen those things. We live near some Union Pacific railroad tracks, and every so often little work vehicles owned by the train company go by. Those vehicles have wheels that look amazingly like those things!