"My opinion: if you're not adapting a trad song, it's just a cover."
Nonsense, there is a difference between adaptation and interpretation.
Shakespeare can easily be adapted, but it doesn't have to be in order to be relevant; it stands on its own merits (with or without Leonard de Capricio).
Our folk songs have evolved - MacColl's comparison of stones being worn away by the constant action of running water always works for me.
A couple of friends of mine have made their names by turning Hamlet, Romeo and Juliet, King Lear (and even Ben Hur) into songs - magnificently hilarius, but no longer Shakespeare or Lew Wallace; enjoyable but different.
Jim Carroll