Marlin,
You are the right man for the job. There is a small market for those restrictor plates, guys always rebuilding their clevelands. At least as much of a market as your pilot bushings, possibly more. If you let people on the Cleveland forum know you could provide them, you would get a few immediate inquiries. I'm also sure you could sell them on ebay, because just like our forum members here, the guys on the cleveland forum keep an eye on ebay for cleveland parts. You could also let Tod Butttermore know you would be able to supply the restrictors for his new blocks, he'll need somebody to supply them.
good luck!
George