There seems to have been a slight consensus building here that for actual traditional recordings(as opposed to written down material) you're better off looking at Patagonia or Maerica where the Welsh may have been more motivated to respect the memories of some material.
    I would make a modest suggestion that you might try looking a little closer to home: England, for example. The Welsh did not just cross the Atlantic: lots went to Cumbria to the mines, lots went to Lancashire and Cheshire, lots went everywhere. At the moment as part of a pproject I am devoting a fair bit of attention to the songs of May Bradley. She was recorded in the 60's by Fred Hamer in the Raven in Ludlow, Shropshire(to be precise,in the Raven pub, as Steve, a phoner-in to radio Shropshire told me the other day). Which tends to place her version of the "The Willow tree"(as immortalised by eliza Carthy), "The Leaves of Life"."The Unquiet Grave" etc as "classic recordings of English folksongs". But we shoudnt foget that May was in fact a Welsh-speaking Gypsy, and like many Gypsies she was a person devoted to remembering and maintaining a stock of very old music. I dont know where she was born, but she certainly spent a large portion of her life in Wales.
   Now, I have never heard that she recorded any songs in the Welsh language. But I would put up the recordings of her singing as very much part of the Welsh tradition. And a hugely significant part too, given the very sad virtually total lack of traditional Welsh recordings. If you get the chance, find her songs and listen. Alas, as far as I know, there is no one CD on which you can find all her stuff(I hope someone can prove me wrong on that one, one will surely be issued any day now).
   By the way, at the Otley Gypsy and Traveller event tomorrow(at the Courthouse, Otley, April 88, 1.30 onwards), Kate Barfield will be singing a few May Bradley songs in honour of a unique performer.