Hello I am from Greece and the use of microtonal notes is very often (if note a rule) in fretless instruments like crettan or politiki lyre, ud an of course the clarinet ( I also play the clarinet) used with a very soft reed tha gives the ability to play microtonal notes.
two of my favorite clarinet players:
Soukas:
Halkias : http://www.youtube.com/watch?v=Lq-U9xHeDoo
a tiny turkish wind instrument called sipsi!
cretan lyra, oud and clarinet
check also the Zurna a double reed instrumen:
Bye!
geokoo