Hi Alan,
my melodica “career” began with a Hohner Piano 36 containing two mouthpieces which you can see here:
http://www.hohner-cshop.de/Melodica/Piano-36/Mundstueck-Piano-36-HOHNER.html
As soon as I had learned how to blow properly into the trumpet mouthpiece, I never again wanted to use any other mouthpeace because it enables you to create sounds never before heard.
At the moment I’m keen on using other mouthpieces such as a bassoon or clarinet mouthpiece to produce other unusual sounds. Has any of you ever tried anything like that?
Andy