Some Concertina manufacturers use "Piano Accordion Reeds" instead of traditional "Concertina Reeds".

Technique: Piano Accordion for The Recycled Muso

Tom Tonon's BluesBox™ Piano Accordions:
See here for details and sound files.
If it is still online, see here
for relevant L.A. Daily News Article.

There is some discussion about the "free reed" - a limited amount of which is in the Accordion PermaThread&trade:, and why although Piano Accordions used an asymmetrical "two ganged single action reeds" form of the reed - in the Sheng in the original oriental instruments, the reed was a single one per pitch "double acting" - i.e. worked in both directions.

The BluesBox™ uses a "double acting" single reed per pitch. This makes it able to be bent in pitch, unlike normal accordion reeds, which only bend in pitch if something is wrong. Wheatstone had woken up to the possibilities in some of his patents, but like the Victorian Computing Machine, the technical problems of designing a working machine eluded him. Piano & Button Accordion manufacturers atuck with the "Classic" form till today.

Makes one wonder whether the current dislike of Accordions - due largely to the fact that the public has an aversion to an instrument so mal-used by many inadequately trained players using poorly maintained out of tune instruments would be better or worse if the pitch could be distorted on purpose as well. But I suppose that the existence of similar sorts of things hasn't really dented the popularity of the guitar in the last fifty years...... :-)

And the possibility of using BluesBox™ reeds in Concertinas in the future - now must not be overlooked. Some predictions of the resistance to change by "Trad & Folk" musos are mentioned on their site.

Robin