I've had a few sets of gears Cryo'ed and REM finished by Jim Bailey over the years, but he sold his business. I heard good things about Evans Performance a bit north of Atlanta, GA and just got a couple of gear sets done there. I may also try the other option they offer next time called "Black" which they say helps retain a thin film of oil on the gears. They also do bearings and just about anything else.
http://evansperformance.com/