Well, I'm not really familiar with gps autosteer, but I'm assuming it is used to guide the tractor from point A to point B while the operator takes a nap or something! I could see where something like that might find use in the wheat, hay, and alfalfa fields around here, which range in size from hundreds to thousands of acres, often a mile or more on a side, relatively flat, and wide open. However, I have never seen a CUT in one of those fields, only large agricultural tractors, the smallest probably 100hp. CUTs tend to be used by owners of smaller properties, and often on wooded areas, and for small fields and yard maintenance. I can't imagine trying to use gps autosteer on my land. Between the trees, rocks, and buildings there are so many obstacles it would probably crash in less than 15 seconds.
Aside from that, the hardware to make it work would probably be difficult to fit onto a small tractor, but never having seen one, I don't know for sure what is involved. I guess it also depends on your definition of small tractor.
