Hi, Anais - I looked, but I got confused. Note that I added crosslings above to the Digital Tradition entry and to the thread on Locks & Bolts. In the thread, the traditional Ballad Index says "Rainbow 'Mid Life's Willows" is on Alan Lomax Collection: "Southern Journey Vol. 7: Ozark Frontier," Rounder CD 1707 (1997), and also on a Vanguard LP.
What confuses me is that I have a book called A Singer and Her Songs: Almeda Riddle's Book of Ballads (Louisiana State University Press, 1970). There isn't a very good index in the book, so I looked through the whole darn (wonderful) book and didn't find the song. However, there's an appendix which has an index for "Contents of Ballet Book." It has the song, but I can't figure out what "ballet book" they're talking about if it isn't the one I have.
So, I'm vexed.
-Joe Offer-