This is happening in China right now. "It is estimated that ten new cities are being built every year." One was even designed for 12 million people. But no one lives in them. "Shops unoccupied, hundreds of apartments uninhabited." It's estimated that there are (now, two years later) well over 64 million empty apartments in China. Yes.... empty apartments.... over 64,000,000 of them. And the Chinese government doesn't care. They're only concerned with maintaining economic growth. Massive building projects count as economic growth.
It's a depressingly sad (and somewhat haunting) reality. Watch this 15-minute news documentary from Australian TV and see for yourself. China is full of brand new, empty, over-priced, never occupied, modern ghost cities. Dozens of them.
At face value it appears they've got themselves the making of a problem. However I'm curious to what extent this report and others (the 60 minutes segment earlier this month: http://www.cbsnews.com/video/watch/?id=50142079n) have been sensationalized. While these reports cite the number of vacant apartments around 65 million, a recent report from Bank of America claims this number may be closer to 20 million (http://business.financialpost.com/2013/03/13/china-ghost-towns/). Meanwhile Stephen Roach (profesor at yale) argues that rapid building is justified by China's unprecedented urbanization rate, some 15- 20 million chinese move from rural to urban areas each year (http://www.businessinsider.com/stephen-roach-chinese-ghost-cities-2012-8). In this context it does make sense for China to preemptively increase the supply of housing. Nonetheless, a sizable portion of those moving to the cities will be hard pressed to afford an average housing price of 45,000 USD.