When I see "spring shop" my experience is limited to work I've had done, but that included the shop fabbing springs from scratch. They had tons, literally and figuratively of leaf stock and coils in house. They asked what payload and ride height I wanted and I rolled out with exactly that. Odds are that commercially (semi trailers, box trucks) a good number of these sets are common and might be economical to purchase but even a scratch fab job was cheaper than OEM (for me). Same day service too. I would think if a shop in po-dunk ABQ could do it then it would be a fairly common resource. Less than common hardware could be a sticking point but it would seem too there'd be an aftermarket or swap solution for that too. Frankly I wouldn't want a sole-source or one-off setup, or you run into a situation like the OP's. Sucks to have to re-engineer something you already bought.
Mark B.
Albuquerque, NM