I saw the photo on page 5 of the May 2006 issue of Farm
Collector. I believe it is something someone has made out of
an old John Deere manure spreader. The engine in the back is
similar to one from a John Deere 12A combine. Where the seat is
built in the front, there appear to be knobs or a handle for some
kind of controls. The steering wheel could be hooked up
hydraulically to steer the front wheels. My guess is that the rear
wheels are also hooked hydraulically to drive them, something like
the way wheels are hooked up or driven on a skid steer loader.
– John Ernst
3242 Utah Ave. N.E.
Iowa City, IA 52240