Hi Erik,
Your post caught my eye because of the headrests. Being a vendor, I don't want to speak out of place here. As you mentioned, we've made these for our Aviator seats for quite a while now. Hopefully I can give some useful information.
The thing we found over the years was that people tend to put a lot of weight on the headrests. Our first headrests seemed pretty strong, but they still got bent out of shape, so we had to make them stronger (and keep them light). If you are just making one for yourself, it probably doesn't need to be that strong. You'll know you can't be too rough with it. You might need to mention it to passengers though.
Years ago we had a customer make a small headrest bracket that was added to the stock seat frame. He had us make a little pad for it. It was very light duty, but it worked for him.
The headrest option on our Aviator seats is $293 in leather (less for other materials). It's the frame with all of the laser cut parts, Cherrymax rivets, mandrel bent tubing, sliding lumbar, visco elastic foam, leather, lots of labor etc. that are the bulk of the cost. Hopefully that didn't sound too defensive. I know the Aviators are not for everyone. If we could make them for less, we would
.
If you wanted to make a small bracket to support a pad we could work with you to figure something out like we did with this other customer. Hope this information was helpful. If I can answer any other questions, just let me know.
Best regards,