here's an Idea. you get a quest from the ruler of one of the BB cities, to investigate one of three villages that hasn't sent in taxes or something. obviously, you save them and the ruler has you help secure resources to build a fort to protect the village. and when it's done, he's so tickled at how you handled the situation that he lets you rule over the area.
here's the real shocking concept: you don't want it. your house is already great, you don't need some stronghold, and all the stress of running a town. so why not have the option to sell it off to some noble for a nice sum of gold? nothing says "OPTIONAL!" like the ability to sell the damn thing.