Well, how about the Yeats poem set to music, "Down By the Salley (Sally) Gardens" which is not the reel Sally Garden, or (and I know he was something of a "wank/wonk") John Denver's "Rocky Mountain High" or "Sunshsine on My Shoulders"? Don't know about the "roots" for those, tho. It's pure corn pone, but Hank Wms Jr's "Jambalaya" does it for a lot of audiences, or "Dueling Banjos". Also, maybe lots of (all?) of CCR stuff---