My husband and I are looking into moving. We've been looking with a couple of friend, who is mono. It would have never occurred to me that it was "weird". I also know plenty of people who lived at 3 or 4 as roommate, and got into relationships, and girlfriends or boyfriends moved in with them. To my knowledge, all of them were mono.
I know less examples of families with children sharing housing with other families, but I do know of some, and really, I know less families with children to begin with.
I'm really not sure what any of that has to do with being poly. If you meant people moving together who are in the same relationship, I would understand your question (the dynamics of a relationships can share if you live together vs not living together) but as it is I'm just not sure what's you're suggesting. It sounds to me like you're trying to reinvent the wheel or something.