Well, I had to reread the thread, as it looked like we were focusing on milspec type guns, but, hey, any chance to yak about my 1911...
I built one on a CMC frame/slide, using essentially no MIM parts. Everything was barstock/billet/forged, right down to the plunger tube (like that matters, but, hey, Ed Brown made one, so I bought it.) Ed Brown Hardcore, Wilson Bulletproof, EGW, SVI, C&S, etc. One piece magwell/MSH was S&A, which they (S&A) told me is not MIM, but is probably machined from a casting. Finding a USGI flared magwell was a little hard. Cost for the whole project was right at $1000.
FWIW, Ed Brown makes a machined-from-barstock mag catch, and SVI makes a machined-from-billet thumb safety. Ed Brown also makes machined-from-barstock MSH's, both straight and curved.
I got virtually everything through my Brownells and Midway USA catalogs, including the slide, and I should have gotten the frame through Brownells, as well. Got kind of ripped there (my own fault). Great experience.
Fun to shoot, too.
Scott
Pic has been shown before, but, hey, it's like my kid...