The alternate history challenge, should you choose to accept it, is to have the CSA survive to the 80s then fall apart like the USSR did. Bonus points will be awarded if some of the Comfederate States go independent like the old Soviet Bloc nations
I was actually working on a TL idea with just that premise some months ago, believe it or not. However, getting the C.S.A. to survive that long, or at least one that keeps slavery until the end, is going to be really tough, and may perhaps require a bit of handwaving, if you want it to survive to the Eighties. It is theoretically possible, however: perhaps the C.S.A. may industrialize to some extent, and may allow foreign imports, and significant amounts of foreign trade, etc.....although all of these could very well require a rather different C.S., and the government would, at some point, have to intervene to keep the inevitable financial bubble from popping. Which means bailouts, and probably starting no later than the late 1940s early 1950s at the latest, and probably earlier than that, if not everything goes right for them.
I do agree with Corbell Mark IV, though: a South Africa type social situation very well develop, especially if a C.S. President or two gets capped, or if a majorly damaging slave revolt takes out half of Mississippi's cotton country, or something. If all the chips fall in a certain direction, that'd probably go a good way towards your goal, IMO.