That's a fair price, let me know when you have the final version and how you want to be paid. You should consider putting this on eBay because these parts are impossible to find. You'd be the only guy out there that's reproducing these. Granted it's probably rare that people need this part but I can't be the only one.
In my case, the PO must have been using pennies for fuses because my harness is badly melted on one side. I've been looking for a replacement part for years but no luck till now.
1980 CJ5, Ford 289, T176, DANA 300, DANA 30, Ford 9", 35/10.50/R15 Super Swamper TSL