I believe that there is no better woman country music singer than Suzy Bogguss (and she yodels!).
Here is a compilation of the kinds of things she usually sings:
I was very pleasantly surprised to hear her do a Duke Ellington tune and sing hell out of it. She is, quite simply, da bomb.
What impresses me most about her performance in these two videos is the lack of techno gimmickry. She could do those tunes just as well in your living room.