Models of the English concertina were made over the whole range of orchestral pitch, although only the original trebles were intented for orchestration as equivalent to voilins. Beyond the bass there is the contrabass, the lowest note of which is 26Hz; the human ear can't distinguish anything lower as a separate pitch. The reed for this note, BTW, is about 4" long, 3/4" wide and has a brass 'slab' rivetted to its free end to slow it down.

While on orchestrations, Percy Grainger wrote several peices with concertina parts and used Duets for them. From memory there are a couple in the Percy Grainger Museum and one of them is a 56 key Wheatstone. Also from memory, the parts required huge chords rather than dexterity in melody lines.

Another BTW; the McCann (Maccann.....etc) is, as far as I know, the only concer you an pick up upside down and still play successfully.

Cheers, Rowan