At that point one might just treat it as a different kind of exercise in urban planning: put as many services as possible under the streets (water, power, data, subways, package delivery, earth-tube heat exchangers) and then you just hook up your foundations up when you build or renovate a building. Porous concrete to allow water to get into the aquifers instead of exiting via storm drains, lots of city parks and green roofs to provide extra cooling and avoid the urban heat island effect.