Just because the top link part of an attachment goes on both sides of the heim joint on the top link doesn't mean you need to. You could easily get the draw bar you talked about and pick up a piece of flat steel. Bend one end and bolt it to the draw bar. On the other end just drill a hole and use a bolt tightened up to the top link. I would use thick steel like 1/4". It's not like a pulling or ground engaging attachment so the forces on the top link will be minimal. You could even use a piece of angle iron, but it would require more cutting.
I saw a picture of a homemade job that someone here had posted a while back. Looks like he used a couple of 3/4 inch eyebolts welded to some rebar, and imbedded vertically in cement. The pin goes through the eyebolt and lift arm. It's not needed as a weight-bearing device...it's just basically to prevent the fore-and-aft wibble wobble of the device, amiright?