I think the first question to answer is why would you do it? Kibbutzim work and they can be wonderful, but they're created often with very specific ideas in min

I think the first question to answer is why would you do it? Kibbutzim work and they can be wonderful, but they're created often with very specific ideas in mind, like a communal way of life or a desire for ethnic homogeneity, not simply 'oh the land is cheap, what if we started a town there'. I can't think of a lot of benefits over starting a private space within the richness and diversity of an existing city, like say the mall idea you mentioned. (which is restricted by law, not by interest. There are legal restrictions that prohibit housing in offices or shopping areas which I think make a lot of sense, but it'd certainly be great if they were more flexible. For example in my city there's enormous housing shortages, and office surpluses, and companies offering to convert office units to housing, but the government rarely changes city planning for which legitimate reasons sometimes also exist, but it can be really frustrating)