Leadbelly lives on in another mysterious way: In a new (2003) biography of Arthur Miller there's an account of a New York party that Miller attened in 1954. Leadbelly was among the guests and sang "Goodnight Irene." I called the author, Marttin Gottfried, and told him Leadbelly had died in 1949. He said that of necessity he gets some informaiton from interviews with and that his source must have remembered incorrectly. He was apologetic.
The book is called simply "Arthur Miller" and it's otherwise excellent.