I just had the occasion to attend a trade show called "Design2Part" in Akron, Ohio.
http://www.d2p.com As I walked the 5 aisles of the show, I realized that just with the vendors on display, one could take nearly ANY part from our cars (or any cars for that matter) and:
1) have it reverse-engineered and CAD drawings made
2) make plastic or other prototypes by 3D printing
3) have it forged, stamped, cast, machined, formed, molded out of any metal, plastic or rubber compound
4) have it plated, painted, and finished
Most of the vendors specialized in small prototype like quantities (the custom spring maker has a minimum of 10 units, pretty low)
If you wonder how some of the long forgotten cars get restored...its vendors like this. I'm sure this show goes all over the country, and it's pretty regional, so when in the SE, there will be manufacturers from that region. Ditto for the west coast.
The array of new technologies using lasers for cutting and forming were astounding. Lots of things formerly needing very expensive tooling are now done with other technologies for lower costs in smaller quantities.