Hi, I'm brand new and am looking to do the army trooper. Anyway, while looking at the flight suit requirements on the CRL, I noticed that it looks very similar to older US Army Utility coveralls. I reanact both WW2 and Vietnam and it just clicked. Anyway, I had read (somewhere in this thread) that you were looking for that.
These are basicly the same (based on what I can tell):
http://www.mcguirearmynavy.com/US-Army-GI-Cotton-Utility-Coverall-OD-Green.html
I have never used this company, but I do know that they list the NSN number, so that can be helpful for people in the future. Hope that helps