dbotos, do a search of my name and look at my posting to another hitch builder. Lots of ideas for that hitch. They are basically what you are already thinking, use the hitch and slide in a piece of tubing and build/adapt whatever you want from there. The 140 Farmall had a 1 point "fast hitch". This can be used as a 1 point reciever hitch. Same idea but using what we can get our hands on easiest.
I see you already have the drawbar and I have one built like that too, works great. Most car dealers take off the heavy towing hitches from their trade in vehicles. They don't want the new buyer to realize it was used for towing, decreases price. So if you know a car dealer lots of times they have lots of reciever hitches laying behind the shop from taking them off. You've already got the reciever tube mounted on a piece of tubing mounting to the frame. Cut it off the desired width, mount your pins, build the upright going to the top link. I use a mobile home spring hanger axle bracket on top of my upright to connect the top link. Could buy them for 1.00 or so and it fits the top of the tubing perfect, just have to drill the hole out bigger. When you drill it bigger the hole gets sort of close to the outside, closer than it would if I drilled it from scratch, but I have several already out in the field working and it hasn't given any of us a problem yet. It saves having to build the plates and drill them, ready made part basically.
There is lots you can do with that hitch, you're basically just getting started when you build it.