In my opinion, Walker Percy is a bit of a sham (though a very good writer). Flannery O'Connor is more gothic than Welty or McCullers; she's practically medieval in her sensibility, with a modern ironic twist. You might try Harry Crews (who is from near where I grew up) or Calder Willingham (who is from where I live now). And of course there's Truman Capote (who along with Harper Lee) grew up near where my father was born and raised.