I have been reading the thread with interest - I live in Chicago, am learning Welsh and enjoying learning Welsh songs - favorites: Lleucu Llwyd, Miliwn (Tudur Huws Jones), a Yr Mynydd (Cajuns Dembo's version of Steve Earle's song) - my band, Hwp-la, did these at our recent Welshfest.
I enjoy Frank Hennessy's show - but there should be a Radio Cymru folk/acoustic music show - John ac Alun and Linda Healy play some, but not enough - the great folk music radio shows in the US, like Folkscene, Midnight Special, and Oscar Brand - could be replicated in Wales, the best, of course, would be a Radio Cymry version of Prairie Home!!
I also was interested in Sian's reference to the Chicago Welsh hymn, Blodwyn. The hymn originally had Welsh words, but, as fewer in Chicago spoke Welsh, my cousin, E. Arthur Jones, wrote English words - a great hymn that is sung at our Chicago gymanfau with great gusto and hwyl.
Perhaps Trac could start a blog and post some of the old songs that are no longer in print.
For recent recordings, I recommend Tudur Huws Jones' Dal i Drio and Dwy Daith from Canjuns Dembo, and all the Plethyn cd's!