Dolly and Millie Good were sisters from a farm in Illinois, but they reinvented themselves as cowgirls from Muleshoe Texas and became the Girls of the Golden West in the early 1930s -- naming themselves after the Puccini opera. Very popular through the 30s and into the 40s, they cut a ton of sides for 5 different labels, yet no-one seems to have collected much of their output in modern times. Perhaps that's because their stuff is pretty mellow - it's just the two of them and a single guitar, so even for cowboy music of the time it's a bit stripped down. Plus they sing ballads. But every so often they get a bit goofy with songs like "Cross Eyed Beau":
They also sing about wanting to be real cowgirls (rather than cowboy's sweethearts):
And while you can't find them on too many compilations, you can find a small collection of tracks at the internet archive, ready to download! To read more about the Good sisters (and to see a full track listing), go here.