Yes, this sounds like a good idea. I may know squat about modding, but you have my vote of confidence nonetheless.
My one and only problem is that there are no real defined borders in M&B, just what cities belong to who. The poor soul stuck with making up provincial borders will have to rely on pure guess work and disagreements will probably arise between people thinking a certain province should be this big, or the Vaegirs should control this much, etc.
But, again, I don't know a thing about modding, so who am I to talk.