I found the Campaign Aid (v1.20) to be a bit too limited in that it gives the feeling that only a few warband's are fighting for control of the city.
In the campaign I am running atm, we have slowly been developing extended rules for what occurs should a warband stay within their current sector in Mordheim instead of returning to one of the three encampments or outskirt city dwellings. If this is the kind of rules set you are looking for, let me know and I can throw over a bunch of our flushed out ideas.
Btw, does Mighty Empires and Mordheim match up very much at all? (Just curious as it does look far too complex, but I am always willing to try out a game if it could be fun)