For all you Iona fans out there, here is another celtic group from Scottland that is rather progressive in their mid years. Their name is Capercaille.
http://www.capercaillie.co.uk
I specifically recommend the recordings:
Beautiful Wasteland and
To The Moon. The couple before that are good too. They blended an african beat in to the celtic sound. Quite unusual when also updating to a more modern sound as well.
Check 'em out and let me know if you'd like to see them added to the moon.