Randy West told me long ago that the buttons come from an Italian company called Breter. I checked their product lineup, and sure enough, they do have buttons that look just like the ones from PYL!
Download this and go to page 13....do those little red and yellow buttons look familiar? The particular model numbers, BTW, are 4090R and 4091R.
http://www.breter.it/files/RM_eng.pdf[you'll need Acrobat Reader...which I doubt anyone here DOESN'T have]