I build one many years ago by attaching an old 9000# electric worm gear winch to a box blade. I replaced the electric motor with a high speed hydraulic motor off an airplane. I built a pair of double pulley snatch blocks and used it to pull up small stumps in my back yard. The box blade could be chained down and it would take the load off the tractor. It worked great until I pulled the worm gear through the housing. It is not the optimal design for skidding with the tractor due to the weight.
I was working on a new one last season until I got hurt. It is simply a hydraulic winch off a 5 ton Army truck that I was putting on skids that would attach to the 3 point hitch. It will pull between 10 to 15 tons. The tractor is used to move it around and to power it. For heavy pulling I intended to chain it down and park the tractor to the side away from the line of fire. As you can see from the photos, I didn't get too far. Hopefully, I'll be able to finish it this summer. Ron