Most B7100s came with B219 or B1630 loaders, both will be hard to locate- people seldom turn them loose once they have them, but you might get lucky.
You might try tractor salvage yards like
B219 is what I put on my 1994 b7100. Remember, hst models are 5 inches longer than geared tranny models. U have to extend subframe if that's the case. I did. No problem for a welder. The rest is just wrenching and making brackets
Is there an plans out there for the B7100hst??? I'm having a heck of a time finding one and aftermarket ones are pretty $$$ just got a quote for $4200!