Fred-
Between Topic and Musical Traditions, I believe that all of Walter Pardon's work is available on CD. MT has also release a CD of George Dunn.

Gurney- Nowt So Good Will Pass is available on CD

There's a pretty good representation of Cisco Houston on "Cisco Houston:The Vanguard Years" and "Cisco Houston: The Folkways Years"

All available from CAMSCO, of course.