Interesting idea. I doubt Jarvis or any top rider runs it. Not enough contact area(Too much of a radius) means less traction. Be interesting what does develop in the enduro cross world. Could trials do similar? I remember at Daytona 200 (1982) I watched with a grin as they had a trials race in the infield! It was good entertainment. The best obstacles were Phillips 66 Balls (like logs) and the handlebar banging on the car was awesome.