This is 1/8" steel, about 18" long and 22" wide. It has a concrete form spike welded in the center. The vertical plate is to make sure that the spinning coil of wire doesn't contact the ATV driver. The two braces are to keep everything square.
It's attached to the ATV frame using existing bolt holes. A couple of pieces of angle iron welded to the bottom of the plate, 4 bolts, and it's good to go.
We used this to deploy four strands about 1200' long each. We could do a 2mph run and the wire peeled off without any problems. The only thing I'd changed about this design is to make the supports on either side out of triangular plants instead of the angle that we used. If the wire chatters and the ATV slows down, a loop of wire can go out that little hole and then catch when you start going again. A solid plate would prevent that.
We also used it to ferry concrete out for the bottoms of posts. Here's 180lbs of concrete on its way out to be used.