Stewart's posting mentioned "Recently some Irish musicians have been composing tunes in odd meters such as 7/8." I wondered about this and then realised that Irish musicians would probably have been composing in odd metres. Under the influence of various characters who've spent time in the Balkans, some of the Irish have developed a love of such things.

A few people I know, who have experience at playing for both bush dances (lots of jigs and polkas and a few waltzes, mazurkas and scottisches) and Balkan dances (lots of really odd metres) used to entertain themselves by adding another beat to every jig they knew, converting it from 6/8 to 7/8. Great fun, as everyone who joined in had a differently stressed rhythm.

It was a different group of people from the ones who played English concertina and who discovered that if you played with your usual fingering 'rotated' one row to the right, tunes in major scales were still identifiable but transposed to a reasonable imitation of minor scales. Such standards as 'Soldiers' Joy' or 'Davy Knick Knacks' instantly became 'Cossacks' Joy' and 'Ivan Knick Knacks'.

The two groups never (in my hearing, anyway) ever got together. Pity!
Cheers, Rowan