Steve

Have you ever thought of doing this?

http://en.wikipedia.org/wiki/Bikejoring

YES!! I got a $5.00 scooter from garage sale and tried this with my dogs one at a time and my staffy who loves ball was horrible at it! she kept trying to look at me and turn around expecting a ball so i was thinking if i got a pole and hung the ball holding it in front of her... maybe we would actually get moving foward.. but then again id most likely crash trying to keep hold of it all. ive also been looking into the dog carts that you can hook up a few dogs to pull.. but they are very spendy! however this is definatley fun fun fun if your dog takes to it!

I tried it with my car and it was rubbish. Blue only manged to pull me 20mph

Yes, but with practice he'll improve!

Maybe I shouldn't use the motorway again until he can do at least 50mph

That's probably best. Once he's really fit & streamlined he'll make your car look like a porsche!