I simply picked up a hitch tube from the local trailer/welding shop, and welded it to my 5' box blade. That way, I can leave the box blade in place and still use the hitch to move trailers around the house. I don't have a pic, but it has worked very well (and is extremely handy). I've moved trailers as big as my Pace 22' enclosed car trailer, and it has held up just fine.
For me, I really have no use for a 3-pt style hitch assembly, as I leave my box blade attached to the tractor the majority of the time. It would be a pain to have to drop the box blade, hook up the 3-pt hitch, just to move a trailer around (especially when I can use the box blade with the hitch). However, I must admit that StanR's design is impressive, and I may weld one up just for the heck of it.