Christopher Alexander talked about that in A Pattern Language, and the New Urbanist architects talk about/design for/build it quite often (the usual solution is the "carriage house" or "granny flat" but more generally the idea is to restrict zoning to address patterns of activity in public spaces, thus legalizing more variation in demographics and behaviors across time and short distances). It does not really fit into the mainstream (suburban) scheme of fastidious homogenization of uses and forms.