I am one that has all the tools you mentioned. I guess I never really thought about the concept of using those tools to scratch build my own parts. When I do sit and think about it I see where I could make rims out of aluminum or nylon. I also see where it is concieveable to make linkage and so forth using small threaded rod and aluminum sheets. I am almost ready to try making my own Headers and so forth.
One problem I do have however is after making some of those small, miniscule parts, how in the _ _ _ _ do you attach them. I have tried and have difficulty to see things clearly under a magnifier and then theres the distortion I see. It just seems that sometimes my fat hands are in the way.
As far as the quality of your builds they are fantastic, I respect you as I do many many others on this forum.