"a 9mm 1911, etc were _not_ among the last 5 guns in the M9 trials."
That's why I said it MIGHT HAVE BEEN!
I don't know for sure and to be honest I really don't care. 9mm guns don't interest me except in pocket guns (IE the Kahr series). Other than the Sig none of the guns tested interest me either.
The reason the 9mm conversions don't work is the 9mm is too weak to cycle a full-weight slide on a 1911. You need to weaken the recoil spring AND lighten the slide to make it work. I guess the Army wasn't willing to do this. After all the reason the M9 trials started was that the 1911s they had were worn out (after only 75 years of service mind you).