(I think all mine are in concert C.

https://www.ebay.com/itm/Schilke-47-Ten ... SwEV5fpYAV
I had no idea how I was going to do four mouthpieces. I thought I was going to have to get a four into one leadpipe adapter and move around like a harmonica player, but hadn't figured out how to cover the three mouthpieces I wasn't playing at the time. All I need now is a two into one adapter with a valve so I can switch on the fly. You are a genius!
There's another one for the "new gizmos" thread: a mouthpiece with adjustable depths that compensates on the fly.