Jamie McMenemy from Kornog does several songs in 7/8. Check out the song Jesuitmont, on their "Premiere" Cd .Andy Irvine does some Balkan songs and tunes live in unusual timings. I don't think any of those songs are on his Cds though. Some of the tunes are.
Martin Carthy does also. Byker Hill is in an unusal timing.
Terry