Shucks, hit wrong button. Sorry. Okay, continuing on:

John Prine & Iris DeMent
USA / Soloists - did just the one CD together
JP via http://www.ohboy.com/
ID via http://www.irisdement.com/
In Spite Of Ourselves, 1999

Kim & Reggie Harris
USA
http://www.kimandreggie.com
Steal Away: Songs Of The Underground Railway, 1997
(many songs also on earlier album, dated 1984

Magpie (Terry Leonino & Greg Artzner)
USA
http://www.magpiemusic.com/
"Sword of the Spirit" (CD dedicated to John Brown)
has now developed into a one-act play.
" Greg and Terry show us what a wonderful thing it is
for two voices to harmonize together", Pete Seeger.

Okay, there's a few. Who's next?