I know what you mean. I heard a good one at a store recently. The clerk was from rural Mississippi. She had a neat accent.i was born there. the really good southern accents are getting harder to find. you really don't ever get much more than a caricature on television, and people just aren't as isolated as they used to be, so you don't hear people say stuff like "yeller toyoter" much anymore.
one of my faves is the accent they used in the movie Fargo. i guess it's a minnesota/north dakota thing. never been up that way, tho, to hear for myself.