The Irish Rovers sing "Lament for the Molly McGuire's" on their CD "Upon A Shamrock Shore: Songs of Ireland and the Irish". A good tune the lyrics can be found on this site:

http://members.cox.net/irishpubsinger/songbook/irish/L.htm

Scroll down and you'll find the lyrics.

A good, bouncing tune which paints the "Molly's" violence as necessity.