You might also want to check out some of the more contemporary bassists who are pulling tons of other influences into their slap playing. Players like Mark Rubin (Bad Livers, solo,
www.markrubin.com ) and Kevin Smith (
High Noon ) are mixing rhumbas, Tex-Mex slap styles, and generally groovy variations into a genre that can be a little by-the-numbers.
I'd also recommend checking out any of the recordings from the
Hot Club of Cowtown , especially their second CD,
Tall Tales.
Western swing (like from Bob Wills and Milt Brown) and old jazz (Duke Ellington's Jungle Band and anything Pops Foster played on) is ripe for the picking too.
And the best-kept secret in the slapping world are players outside of the American mainstream styles. Check out Norteno music (like Santiago Jimenez ---both senior and junior) and Roma gyspy music from Romania. The Taraf de Haidouks are amazing. Truly amazing.
G