Wandering off topic here, but Sedayne, that Stylophony track is something else. I think I have to get myself a Stylophone after hearing that. Quite right about modes and tempered scales. I love to hear untempered intervals in folk music.

Getting back on topic , accompaniment can take many forms, drones, counter-melody, close harmony, block chords. A good accompanist knows this. Chords aren't the be-all and end-all of an accompaniment and they certainly aren't the End Of The Tradition As We Know It.