About five or six years ago, the church I used to go to in Madison was offered some land to build a private school on Highway 22 between Canton and Flora. The church opted not to do that at the time because of some other issues that were relevant, but that does seem to be the next spot for a private school.
As far as public schools go, Madison County Public Schools built the Madison Crossing campus with a high school in mind. For those of you who don't know where that is, it is east of I-55 towards Deerfield. They could build and open that school without any governmental oversight * if it did not change any of the attendance zones.
* for those of you have kept up, the Madison County Schools were under consent decree since the late 60s/early 70s and finally got out of it in the early 2000s. (I don't know the details of why the system was under the decree. Maybe somebody else does.) While under the decree, EVERYTHING had to be run through the justice department and they always had a better idea.
Since getting out from under the decree and since the school system has adequate cash, they can do pretty much whatever they want to, witness the massive expansion of facilities at Germantown High in Gluckstadt. A member of the school board told me that since they did not have to bond out the projects, they could do it as needed. He added that a bond issue will be advanced for Madison County in the next few years to address other needs.
FWIW.
PS - My ranking of Private schools
St. Andrews - Berkley - smart but weird
J. A. - Ole Miss - Style over substance
Prep - Georgia - pretty smart; pretty good
MRA - Oregon - used be be nowheresville and now are relevant
St. Joe - USM
Hartfield - Jones CC
Tri County - U W Whitewater - small but good
Canton - West Alabama - they compete