Do a Google search on "southern progressive rock" and you might come up with a few relatively unknown bands.
But then there was The Mars Volta from El Paso, Texas. The sad word here being "was." But that's the sad thing about music. Bands come and bands go, even the good ones.
The Mars Volta wasn't just good. It was tail-kickin'. Coming from Texas, the land of cowboy boots, that's not surprising.
Just don't expect much in the way of "good ol' boy" flavoring from these guys.