TAs has been mentioned, Adam McNaughton is worth a listen, as is Con 'Fada' O'Driscoll; between them, have made magnificent songs on Hamlet, MacBeath and King Lear. Not as good as the real thing, but well worth a visit.
Con Fada has also done a very full version of Ben Hur (available in the book, The Spoons Murder).
The MacColl double album 'The Paper Stage' has a number of broadside versions of plays, including King Lear and Titus Andronicus.
Jim Carroll