I haven't ever thought of that idea. But I don't think Ash would be very happy if I put him in one of those things lol. He'd probably get freaked out when it started spinning. Personally I wouldn't use one for Ash just because he would be really scared in something like that.
Rabbits can't use a running wheel or ball. Hamsters and gerbils have a much more flexible spine, rabbits do not. A rabbit has a long stride that could not be accommodated by a wheel.
It is better to just let a rabbit run around on the ground in a safe area.
NO, no, no! Please don't even consider such a thing. I have also heard that because of they way rabbits move (they don't "run" like gerbils & rodents) that such a wheel or ball could cause severe injury to a rabbit. Just let the bunnies run in a bunny-proofed room or in a large outdoor run.
I built my rabbits a wheel and they love it! They use it constantly. It's much larger than the wheels you buy for small animals at the pet store. It modified it from plans for a cat wheel. As you can see in this video, they can really get going. And they like to use it together sometimes. http://youtu.be/RFlqkkW4he0