I just listed these 2 tapped controls on eBay. Seems these are hard to find in this like new condition any more.
Tapped Volume Control Pot Potentiometer Tube Amp 85 K - eBay (item 170670384198 end time Jul-26-11 10:21:56 PDT)
Tapped Volume Control Pot Potentiometer Tube Amp 100 K | eBay
Tapped Volume Control Pot Potentiometer Tube Amp 85 K - eBay (item 170670384198 end time Jul-26-11 10:21:56 PDT)
Tapped Volume Control Pot Potentiometer Tube Amp 100 K | eBay