Someone already mentioned that all the Carradine brothers can play. I believe that whichever one was in Altman's Nashville not only performed his featured song ("I'm Easy"), but wrote it as well.

Congrats on teaching Ms Nixon, Frank. Her work generally involved stand-up vocalizing accompanied by full orchestras, so she probably didn't use the guitar professionally very often if at all, but I'm sure she enjoyed it, and her obvious musical talent must have served her well as your student.