You might try Worthington Ag parts. They have several wrecking yards across the country, with a good selection of parts machines. I have ordered some used combine parts from them, and they were in good condition, and the price seemed reasonable.
Really, how much did they want for a set of straw walkers for a 7700IJ I bought a longer unloading auger for my machine from them because mine was too short to dump in a semi. I think I paid $500 for it plus freight.