A few concepts & ideas I'd look at include;
Smith and Wesson M&P parts & custom work. The new Shield line is growing with the concealed carry crowd.
Id also look into joining the APG;
www.americanpistol.com . That's the American Pistolsmith's Guild.
Parts & custom work for the M9 and 92/96 series pistols are rare. David Olhasso,
www.Olhasso.com seems to be one of the few gifted pistol-smiths for Beretta models. Ernest Langdon was highly respected too but he left the industry to take a exec job with a major US gun maker(S&W I think).
The M9 & M9A1 has been a US military sidearm since the mid-1980s so there are 1000s out there. Parts & gunsmith tools should be available to your firm.
Id add that Cylinder & Slide;
www.Cylinder-slide.com & Larry Vickers(a retired US Army spec ops trooper) are known for gunsmith classes/skill training.
Bruce Gray of Gray Guns is known for HK & SIG Sauer P series pistols. He may teach new pistolsmiths too.
ClydeFrog