I'm surprised that Skip Gorman's name hasn't come up. I believe he has 3 CD's out 2 of which I play often & as far as true cowboy songs he's gotta be one of the best. His research into the music is invaluable & it shows through in his singing, he's also I believe a champion fiddler in this style & yoddler/singer. Some of his backup includes Jeff Davis, David Surette, Connie Dover, Ken Sweeney, etc. Anyway I can't recommeend Skip high enough.

Another CD to check out is from A. Lomax's collection of "Deep River of Song" on Rounder, this volumn is called "Black Texans-Balladeers & Songsters of the Frontier" Like with shanties Blacks made up anywhere from 10%-20% of the laborers in this trade/field & recieve hardly any recognition or credit for their huge influence in these areas of music.
Good Luck

Barry