Well, if you can do it at an acceptable market price you may have a business opportunity, and all speed to you. Many of us clearly don't see how it could be done, so a prototype and a patent filing could be good next steps.

As an example, a Canon EF 50mm f/1.2 L costs about $1350. A used Canon FDn 50mm f/1.2 L can be picked up for between $450 and $700, so to be worthwhile a motorized adapter would need to retail at say $250 or less, which would mean a manufacturing cost of say < $100 and a very small market unless it worked on several FD series lenses. That would assume that it could have close to equivalent optical performance to the EF 50mm f/1.2L and equivalent functionality. If you can design something like that, then there could indeed be an opportunity, since most of us don't seem to think that it is simple enough to do. Perhaps you do have the magic sauce here and we just don't see it.

The TC-16A still needs a focusing motor, the one in the camera body. It only works on a few Nikon bodies and is only meant for fast lenses. They made the TC16-A as a stop gap device when AF was becoming immensely popular and NIKKOR had a limited selection of AF lenses. If it was such a great idea then why didn't they, Nikon, follow up on it. Because it was a temporary solution to a fixable problem.

Making such a device for modern Canon DSLR's would be cost prohibitive. Not only would it need an on board focus motor, something the TC16-A didn't have, it would need an on board CPU and the correct firmware to make it all work. Canon's not going to make one and I seriously doubt they're going to supply anyone who would attempt to make one with the necessary software needed to make it work correctly with Canon products.

It is an interesting idea but in today's fast paced high tech digital world, not very practical.