My good friend and I made modifications to his bumper (24608) on his new tractor (28903).  He needed to be able to move his boat and other trailers through his yard at ease.  We came up with this: 1.5'' steel bent at a 90 degree angle with a hole drilled in the center to add a ball hitch.  We bolted and welded it to the bumper on his tractor.  We looked around at purchasing something like this and it has not really been made yet.  The steel on the rear of the tractor was not engineered for moving object like this.  We came up with this idea from watching airports move airplanes around.