Rusted Rocker Panels

Does anyone know where I can buy some rocker panels for my 1998 Expedition? Rusting and want to replace, Ford wants to sell me the whole door shell area. Looked online but can't find for Expedition. I can't be the only one with this problem.

Figured I let you know what I had done. Body shop bought 4 rockers for the ford truck and he fabricated them to fit. Looks great and no more rusted rockers for now.