Last year, I asked Hohner about melodicas for the previous generation. The Airboard Rasta one (check out the tube segments) etc. were advertised as the Melodicas for the new generation, or fluff like that, and I wanted to make the point I just wanted the solid version, not the flavour of the day.
One of the items in the exchange was that their Performer 37 wasn’t limited to white tubes, but they sold black tubes for it as well. Of course, that leads to the Soprano and Alto that white and black mouthpieces exist for. Ultimately, you’d have tubes of differing colour, of selectable length, with a standard connector going to a mouthpiece of your choice, and at the other end, again a standard connector, here connecting to the instrument-connector for the specific instrument you are playing. (More complex stuff is possible.)
Indeed, it all looks doable, though the best way for the connectors might require some testing. There may not be a market anyway, though.
So far, I’ve assumed that they ended with these plastics, with the logo on the front. Before that, they were using green boxes, some time after the Altos were added; the logo was on the back on those. Before that, there was no colour-coding, with the Soprano having a red box. Going back even further, there was not even a “Soprano” on the box.
The Soprano that doesn’t show a well-shaped mouth-piece really doesn’t have a mouth-piece at all.