Snowy, i know this is a late reply but the closest thing i've found for a Leadbelly interview is his Last Sessions 4 cd set. It's Leadbelly singing his songs amd some classic folk tunes and talking about 'em in between. Well worth a listen for anyone interested in the man & folk song history.
Alan Lomax recorded hundreds of his songs live. Many are available on Smithsonian Folkways. They actually travelled together for some time, until Leadbally threatened him with a knife, and that pretty much ended their relationship.
I have some mixed feeling about the Lomaxes They went about recording music and saved a lot of music. But, they also stole a lot of music by recording and registering it in their names. I don't know if it was the Lomaxes but this is what drove Son House to stop singing.
just out of curiousity...did anyone ever,interview and record him? Is there anything of leadbelly,say..on a radio broadcast and not just on a musical recording of the day?