There is a short piece with some links here:Bastin's 'Red River Blues' is the definitive work on the subject. Also his essay 'Truckin' My Blues Away: East Coast Piedmont Styles', which is chapter 6 (pp 205-231) in Lawrence Cohn (Ed) 'Nothing But the Blues: The Music and the Musicians' Abbeville Press, is a wonderful overview.
In respect of Curley Weaver, there is a lovely CD available where he accompanies Blind Willie McTell and takes lead vocal on 4 songs: Blind Willie McTell and Pig'n Whistle Red 'Same' Biograph BCD 126. Curley's pseudonym was the name of the barbecue stand where McTell and Weaver played for tips.
As has been pointed out, there was considerable interaction between white and black musicians in the region. To Rick's list above, I would add the great Frank Hutchison. Also Dock Boggs' banjo playing was influenced by black sources.
In his 'Blacks, Whites and Blues', Tony Russell gives a beaut anecdote relating to the late John Jackson. A friend was talking to Jackson one day, recounting the story of DeFord Bailey and his unique position in the Grand Ole Opry. 'John was puzzled. The only black artist? What about Uncle Dave Macon?'
--Stewie.