Coincidentally there are a few VERY good ultra runs in central Alabama, but none in the souther part, that I know of. There are also some in GA that are closer to the south, near Columbus, GA. I would HIGHLY recommend checking out the Pinhoti100, www.pinhoti100.com The Pinhoti trail is a 500 mile trail through the Talladega National Forest in Alabama, that now connects to the AT. The Pinhoti100 this year will run November 6th or 7th. Some have called it the Wester States 100 of the south east so its definitely a fun and challenging race. Check it out!
You might find the pinhoti trail alliance website to also be informative. The Pinhoti trail is beautiful and peaceful as not many people know about it.
Also, there is the Mount Cheaha 50K, also run on the Pinhoti trail in Feb/March. http://www.pinhoti100.com/mountcheaha50k/
Todd Henderson is the race director for both races and he lives in the area. You can find him on Facebook. He also frequently organizes some training runs on the actual course. Wayne, a fast local does ultra training runs every weekend, ask Todd to put you in touch with him.
I've been living in Alabama for 4 years and luckily only 5 minutes from a good Pihhoti trailhead but unfortunately the company I'm working for decided to move our facility far away so I'm out of a job. The next job I'm getting is taking me far up north (Wisconsin) in a few weeks. Otherwise I'd welcome you to stay over and do training runs with me...
Best of luck!