Here in Belgium there's a village that's famous for doing this. Currently there's about 100 people there who are living with another family. https://nl.wikipedia.org/wiki/Gezinsverpleging_(Geel) If you translate you can read about it.
Less acceptable currently, other alternatives? Still seems famous and popular, just not quite as much as it used to be.
[1] https://en.wikipedia.org/wiki/Geel#A_model_of_psychiatric_ca...