Several have mentioned here that JP ships a Wick 4AL with their euphoniums. However, they sure looking and feel like Wick SM4U mpcs to me!
On the mouthpiece front, here are the others I am currently still dancing with and/or willing to sell.
(Wick 4AL, Bach 4G, Schilke 52D, K&G 3D, Wick “Heritage” 4AL, Mercer & Barker Solo51, Warburton Demondrae, Alliance E2)