I built a drag around system to use is conjuction with my tractor mower. I used it for a couple of years until I upgraded the tractor to a 52 inch. In fact, I just got rid of the mowers recently.
What I used were a couple of 20-inch mowers each with its own engine (they were free). I removed the front wheels and bought a couple of HF air filled swival units. I had to fabricate some brackets to support the wheels I also made them adjustable. The drawbar was made from 1 1/2 inch square stock. I used two sizes so they could slip into one another and make the wigth adjustable. The hitch was a ball hitch also from HF. Since my tractor has a sleeve hitch I incoporated some rods that connected to the hitch. I have a lathe I made some swivels so that he mowers would track on uneaven ground. As for the mowers I removed the handles and removed the blade break. I installed a couple of brackets and installed kill switches. I ended up with a 72-inch cut. It's not a great setup if you have a lot of obstacles.