I don't know why i haven't shown this yet! well, time to get this off my mind. Im waiting for someone to scratch build this!
http://www.youtube.com/watch?v=swsihXKrchY
http://images.google.com/images?hl=en&um=1&q=orange+blossom+special&sa=N&start=42&ndsp=21
sorry about that last link, couldn't get the picture alone. Anyway, all i see is u need a john deer caterpillar tractor and a cheap toy train.
Why wait for someone else to scratch build the model? It sounds like you know what is needed. How about going ahead and doing it.
After watching the video, it occurred to me that this would be a great vehicle for getting around rush hour traffic. Or more correctly, for getting over it. As for people who deliberately cut you off ...
Jim
hmm, good idea! its a good starter and even if i do screw up, it won't be a huge lose.