Junk yard or salvage yard is probably your best place. That is rarely a take off item so finding one laying around might be tough. Wheat country might be a place to start, but I suspect they are pretty much standard equipment out there as well.
Check with Cole Implement....that's where I put our kit together, with a used HCC front part and the new style controls. Worked on the throat a bit, and we are extremely pleased. (it's on a '94 62) Not cheap, but works good.