Melodica arrived! It's a thing of great beauty, with three whole octaves of notes, all of which sound - and the wind-source doesn't make any noise at all. Proper job. Sustain is going to be an issue, though, as is the volume difference between the low and high ends of the scale - melody-over-drone sounds a bit like canary-over-HGV!

On the air pressure front, it's not set up to take constant air flow like a fan-driven reed organ, so I can imagine it might complain if I drove a lot of air into it forcibly. I suspect the constant pressure of a bag might be a better option than pumping it directly. (And there is an air button.)

Manitas - if I can reinvent the bagpipe with a £20 melodica and a wine box, I think I'll be well ahead on the deal. (I can even drink the wine!) Also, a chromatic bagpipe would be something to behold...