Try some of the early Sons of The Pioneers when Roy Rogers was still Len Slye. With Hugh and Karl Farr on guitar and fiddle, Tim Spencer-guitar and vocals, Bob Nolan - songwriting, bass and vocals, Len Slye - guitar and vocals, they had the closest jazz harmonies including 3-piece yodel harmonies, as well as instrumental breaks from the Farr brothers that equaled anything done by Eddy Lang and Joe Venuti, or even (dare I say it?) Django and Stephane. Some call it Western Movie music, but I believe it's among the tightest Western Swing sound you'll hear. My opinion.