well I am not going to say its SAFE to do so, but I have used a 3 way hitch set up for about 15+yrs now and have had trailer behind my smaller 400 foreman that have weight in well over 4,000 lbs+, and a ton of times 2000+ lbs , I will admit I am not traveling far or up and down any hills, but I have had some serious tongue weight( I have bent the ball holder downward some what from it) on it and it has not caused me any issue/s for me?, but again, I cannot guarantee you will have same results as me! But I have been very very happy with this set up, allowing me to use smaller Pin mounted trailers, and or ?? and still keep the ball in place!
if you wanted to MAKE one of them I gather it would be pretty darn easy to do so!, if you don't need a Ball on the atv, you can just stick a clevis in the ball holder and have sort of the same thing?(would be wrong way vertical rather than horizontal for the ring like, but, if using to attach things to, it would still work?