Back to the OP: I would not go buy a new outfit at one of the suggested retailers if you don't want. You have a suit, I suspect. I would wear that suit. Who will say a suit is not "genteel"?
A middle ground: wear your suit but spring for an accessory from the recommended sources: a piece of neckwear (tie, bowtie, or ironic bolo tie), an ironic hat, suspenders, spats...(a friend of mine was sporting spats recently, so they come to mind as a gentleman's hipster accessory).
p.s. I am not from the South but I do mingle with hipsters.