Juat to clarify: Lonnie's Rock Island Line Line was recorded in 1954, but was a hit single in 1956. And it did have a cheap old washboard on it. But by the time he was releasing Dont You Rock me Daddy-O(which was a single too) he a perfectly conventional electric guitars, drumkit etc.
    He was also, which nobody has mentioned so far, a GOD! I started a skiffle group at school in order to worship Him.