As far as hobby grade ones, I don't believe any exist. But, when my boys were younger we had a real blast with these. A Tyco Rebound:
http://cgi.ebay.com/ws/eBayISAPI.dll...5171%26fvi%3D1
They're not very big and drive like a tank (4WD). A real riot.
They also had a bigger version, called a super Rebound. We had the first generation. Ours had blow up tires and a 9.6V batt. I don't know how well this one is, and a bad pic but the only one I could find. Here's an example:
http://cgi.ebay.com/ws/eBayISAPI.dll...9599%26fvi%3D1
They have come out with a new version I see:
http://cgi.ebay.com/ws/eBayISAPI.dll...8903%26fvi%3D1
If you want some more fun try one of these. Again, we had the first generation, but this still looks to have the leaning driver that shifts the weight, steering the free floating front wheel. We had lots of fun with it until one of the boys drove it through a puddle.
http://cgi.ebay.com/ws/eBayISAPI.dll...1521%26fvi%3D1
They are cheap and can't replace parts, but they are great fun for the kids. Thay take quite a beating and inexpensive way to teach them about RCs. Try searching for Tyco Rebound on Ebay or other variations and see what pops up.