It's possible that the source of the problem in my previous paper pipes project was the flexibility of the card that it was built from. The card flexes and everything moves out of line. With that in mind I thought I'd revisit corrugated card pipes. Unlike my previous efforts with corrugated card pipes (more of which later) this time I'm aiming at a high pitched pipe compact enough to be fitted with an integrated set of bellows. 

I have a few different ideas to try out, starting with this. The air goes in through the arrowed slot with the dark hole on the top surface being the throat where the sound comes from.

Viewed from the underside, the air inlet slot is on the left. On the right is the tuned tube. 

Mk 1 works but needs a couple of tweaks. I have a few other designs to try out as well. I'll be reporting progress as I go.