It's funny, Unicomp is based out of Lexington, the place I moved from and left my old keyboards there
I once called them to see if they had a particularly rare buckling spring keyboard in stock and they said they did not but offered to sell me one very similar at a discount. From the way the person on the phone talked they're a very small, engineer led company.
and yes, the unicomp customizer IS a model M. Not sure I'm gonna drop $80 for a new one though. I'll hunt for a while or try to trade.
Once I do get a model M I might email them and see if I can get a nice set of those grey keycaps from them.