If you can rig up a bellows strapped to one arm, with a tube leading to a bag as in bagpipe under the other arm, with its output tube connected to the mouthpiece, then that would look very impressive. But in reality, I’d have thought you’d be as well to just use an accordion on single-reed setting. If you can get one with a cassotto, that might get you a slightly more melodica-ish sound.
I forgot to mention that I don’t want to spend a lot of money doing this–otherwise I definitely would just buy a harmonium or accordion. That bagpipe idea sounds really cool, though…
