I can think of at least one product that will do, basically, what you describe. It's insanely expensive to license and setup. It would probably be feasible to

I can think of at least one product that will do, basically, what you describe. It's insanely expensive to license and setup. It would probably be feasible to fork the RANCID network device configuration version control application to create something that could do what you're describing out of FLOSS components, too.