But if you've been attracted to the Hayden because you like the idea of being able to transpose by just shifting your hands but keeping the same finger pattern, MIDI now provides essentially the same option for any layout. Instead of shifting your hands, you just flick a switch, and all your fingering can remain exactly the same.
Applying MIDI (or any electronics) to the squeezebox has three parts: first, "keeping the same finger pattern," second, "the same option for any layout," and third "feel."
I'm not so keen to propagate peculiarities across all key signatures, as I am to make things as uniform (and simple) as possible, so the first is more interesting to me. The Hayden layout is mathematically logical, canonical, as every aspect of music ought
to be, IMEO.
The musical relationships remain constant among an infinite field of buttons. I don't need an infinite field, but it would be nice to be playing from a position (home base, tonic) that was never hindered by edge effects. That would need the ability to map a limited but sufficient array of physical buttons to any part of the theoretical infinite field.
The second I wish to have mainly for others. Although I play Anglo-Irish as well (but not very well), I myself am not so keen to twist a twelve-position switch to be able to "crank up or down" the idiosyncratic 30-button arrangement to any key signature, like the legendary piano of Cole Porter (who was said to be able to play only in one key). But I don't begrudge those who would like to apply the same key-shifting techniques to other layouts for pragmatic, practical reasons, (playing in the same key as the tuba, for instance).
Third is the risk of losing the feel, the kinesthetic response of gesturing with a physical instrument, what we have taken to calling in the most recent half century, physical or sensory "feedback." It is possible (and perhaps has been done) to create a concertina MIDI controller which would completely decouple the player from the physics of making free reed music. Besides replacing keys with pushbuttons, the bellows  could drive a wind-controller instead of selected reeds, or control voltages could be generated by the amount of stress put upon some elastic medium substituting for bellows.
For me, that would be a great loss. The gains on the other side of the balance sheet are well known: all the plusses of making music with MIDI. Changing buttons to pushbuttons is not a great change. I play cheap, old Hohner, Bastari, and Stagi instruments. I recently had the privilege to try the Tour Tedrow. Compared to my instruments, the Tedrow is snappy
. People who have good instruments like the Tedrow would probably make the same remark: a switch to electrical pushbuttons would just make the feel snappier. It might even be perceived as an improvement, but surely not much of a change, as long as there are real, bellows driven reeds.
So the cat is out of the bag now. I'm thinking about an instrument with an electronic keyboard (buttonboard) with programmable coupling to a set of electronically operated valves controlling real, bellows-driven reeds. Such an instrument could also contain air pressure sensors to function like a wind controller. It should be possible to make this instrument as light as a conventional box. The car battery power supply might be another matter!
If anyone else wants to run with this, be my guest--just remember you heard it here first!
* * *
 There is an opportunity here for a long ramble, a deep discussion about the relation of the bellows and its action to breath and pneuma
. Another time.