What do their CSA insignia looks like?
I guessed that the greatest issue would be the lack of any suitable terrain...
As for scenario, given the fact that making a campaign with the CSA is an uchrony, we are quite free. I've thought of a timeline (sort of) and tried to find a cause for war in the 50's -60's - 70's or early 80's (our favorite sim time frame, in other words). I found ideas centered about some cuban issues, but other way can be explorated too.
As for the aircraft, I do not know quite well american aircraft builders, especially their history, but maybe were historically some compagnies born in the South, and other in the North? Let's say for instance that historicaly Mc Donnel Douglas was founded in Alabama, then CSA shall get F-4. If it is not the case, one can also use arbitrary choices ;) And don't forget that in most uchrony, CSA, France and UK seems to share close bonds, then the option of giving CSA french and british equipement might be considered too.
Except from story line and some ideas, I can't do any "hard core" modding (map, skins etc) so if someone is interested, feel free! Actually, I had this idea washing my dishes and thought "hey, I have to post it on combatace to see if someone can be interested". :)