Note: This is little more than rumination on my part, but I am interested in what people think about it. I am not now (nor will I ever be) a southerner, so this is just an outsiders opinion
Over the past few election cycles, the Southern states have moved further and further out of the grasp of Democratic politicians. Even the races we win, we win by nominating Republican-lite (or not so lite) conservative Democrats whose policies are little different than those of the Republicans they replace. Even these conservative Democrats are often hurt by their association with the national party.
Perhaps what might work is the wholesale departure of the Democratic Party from the south (with the exception of Louisiana, Arkansas and Florida) and the founding of a regional progressive/populist party 'of, by and for' the South. This hypothetical People's Party, led by African-Americans and poor rural whites might stand more of a chance. At the national level such a party could work in an alliance with the Democrats.
This arrangement can be observed in countries like Germany, where the moderately conservative Christian Democratic Union leaves Bavaria to the more socially conservative Christian Social Union. At the federal level, the two form the CDU/CSU alliance.
It's just a thought, but perhaps this Democratic/People's Alliance could better capture the "guys with confederate flags on the back of their pickups" (to steal a thought from the good Dr.)