I can't call it "facts" or "data" and I don't know their actual political leanings, but the Pioneer Institute for Public Policy Research has a shiny PDF file detailing several issues and proposed solutions; for instance, the article claims 10 towns outright prohibit multi-family housing, and 9 more only allow it for seniors. Their suggestions do tend to match the sorts of things the anti-40B crew thinks would be better regulations and would spontaneously appear in the absence of 40B