Wales

So, this is a perhaps, unusual question but I thought it might make a good resource post for other people.

Anyway, out in meatspace I do hospital radio show of a Sunday, which specialises in Scottish music - mostly rock and pop but with wee features on unsigned/up-and-coming bands and folk music. Every so often I like to mix things up and do special editions of the show (eg for St Patricks Day I did an Irish version) and I wanted to do a Welsh version of the show. Now I have music by a decent number of Welsh bands and singers (Manics, Stereophonics, Catatonia, Super Furry Animals, The Automatic, Lost Prophets, Tom Jones, Bonnie Tyler, Jem, Charlotte Church etc) in my collection but I don't know very much about unsigned/up-and-coming Welsh bands (I was recently introduced to Cowbois Rhos Botwnnog but that's about the extent of it) and even less about the folk music scene in Wales.

Therefore this is a request, for whatever you can tell me about Welsh folk music. Are there other traditional welsh music forms that I should be introducing my audience to? Or perhaps up and coming Welsh indie bands that incorporate traditional or specifically welsh instruments?

Also my quick and dirty google and last.fm searches for welsh music comes up with a lot of welsh-language rock and indie, is this representative of the welsh music scene or did I just stumble into a niche? (A lot of them seem comparatively successful, at least compared to their Gaelic language conterparts up here)