I am glad there is someone in our community that has the interest and ability to address such a low volume reproduction process that you are suggesting.
Personally, I have long envisioned a not so distant future where many homes have desk top 3-D printers, allowing simple replacement parts for appliances and other home items to be made in our own homes after the purchase of a one time use file. But I digress ...
You are correct that the ignition switch electrical harness is a critical part that is no longer being manufactured. That does not mean it is anywhere near to being unobtainable. I made a small bulk purchase of new old stock pieces less than two years ago from a vendor in the UK. Prior to that another UK vendor had sold me approximately 60 pieces that I sold through the years.
In addition to the original pieces, that electrical piece, remaining essentially the same except for the method of mounting to the lock cylinder portion, was used on later Ford vehicles and those switches are even more readily available than the ones used in our cars. I ‘think’ the later version’s internal pieces duplicate the early units, so just creating a proper housing and swapping the guts from a new switch would be another method to create a Pantera-correct switch.
Please feel free to send a private message if you would like to discuss this issue privately.
Larry