This is a response to VC 27 Larry 11 ("Interesting, but...")...
Thanks for commenting Larry.
The crux of the idea is to make housing larger than the minimum unprofitable and so expensive that a person would not buy a house with any hope of later profit and only buy a large house as conspicuous consumption - to show off their wealth.
Most people expect to make some money or save money on the house they buy. If they are fairly sure that it a losing proposition, reguardless of what the economy does, few will opt for the larger house. The result will be more available land plus savings on energy (almost as good an effect as population reduction).