When I originally became interested in concertinas, I wanted a duet.
However, they were expensive, somewhat rare, and rumored to be very difficult
to play (except for the completely unobtainable Hayden duet). I finally settled on an english...
but when I set out to build one, I decided to build a duet. As long as I was building it from scratch,
I thought I might as well use a sane key layout, so I settled on a 48 button modified Hayden layout.
It's modified because I didn't want to commit to building the action, reed pan, etc., for the number
of buttons in a full Hayden Duet. And also because I generally prefer smaller & lighter instruments.
Here's a picture of the layout I decided on:
Project Index | Concertina Project