LOVE it.
My exBF has proposed we do this with my family, me, him, etc. We'll see.
I've lived (though not with my family) in this type of arrangement. My thoughts from that:
-if anyone is super ideological on any count that differs from the group's "mainstream", to the point that they REALLY want everyone else to share the ideology, don't bring them in;
-allow each person not only their own little home, but also a personal yard space that they are free to fence -this prevents lots of concerns pertaining to pets, gardening styles, privacy boundaries;
-encourage the use of a "do not disturb" system or better yet a "do disturb" system, regardless of how much everyone likes and enjoys each other;
-give the collective first right of refusal if anyone wishes to sell their share;
-give the collective total say in who moves in, and an excellent plan for funding any shares not currently covered by anyone (e.g., empty home)
In BC, Canada -don't know if/how many other places- we have an option of a mixer mortgage, allowing people to share space yet each be responsible for their own portion/debt.