Yeah, I was (am) going to do that to my JD-770 (one of these days) and I looked all around also. I was going to go with I believe W.R.Long as you can download a form and fill out the dimensions of your loader/pin setup and send them in and they would make you one. Can't remember the specifics. As far as the bucket the 'Tube had a few guys that showed how to DIY it. I do want to save the bucket on the JD as it is really robust and I still do use it a lot.
I do have my LS now and it certainly is nice having the QA and the wife does like the auto tranny but she feels more comfortable using the smaller JD. Having the QA on the JD would help out as I could have the wife move some stuff for me with the forks so I don't have to stop farting around playing with the LS, I mean stop working on my project.
I was leaning towards the full bracket between the arms so it would (in theory) have some twisting prevention strength when using it to shove stuff sideways or offset heavy on one side like, dirt, gravel, rocks, etc.
We do have a couple of welding shops around me so if I don't feel confident with my welding then I can take it to them to have it done, I can't think it would cost too much and having a little more peace of mind helps.