A simple google search for engineering consultants will reveal a massive number of them here in Atlanta. Ranging from monsters like Jacobs all the way down to two guys working out of their basement.
A lot of environmental as well, dunno what your focus is. Many in the Norcross, Roswell, and Marietta areas. I know that requires moving into the city but if that is the change you are looking for, then go for it.
Working in Norcross and living in Johns Creek would be a good setup. Its nice up there with nice schools. Being able to get to work before 285 is a plus.
A few firms downtown but unless you are ready to do the whole intown living, it might be rough.
Dunno, just some suggestions.