A talented artist from the Netherlands (I think) named Pheugoo has created a couple of mash-ups featuring hip-hop vocals over c&w music. Yee doggies, this stuff is good:
Usher's "Yeah" vs Jerry Reed's hillbilly pickin' soundtrack music to "Smokey and the Bandit"
Limp Bizkit vs that cowboy classic "Rawhide," as performed by the Blues Bothers. This one works so well you will actually enjoy listening to Limp Bizkit. Almost.