A more apt comparison would be suzhou. Areas of it were developed under singaporean authority. The singaporeans ended there with huge losses, and I don't think they are interested in doing such anymore.
And singapore and china are relatively close culturally - if for example china were to setup cities in Africa, diaster would occur. You can see the same happening with current chinese ventures there: they are run and managed solely by chinese and employ chinese. I was watching a BBc documentary the other day about some chinese companies in Angola, and an Angolan man complained: "Why do they need to bring people from China here to drive trucks?" The answer is simple - if you have people from two different countries and two different cultures where one is driving a truck and the other is managing his work, then productivity will sink massively.
A country administering a town in another country will be constantly beset by these cross-cultural problems. There will be conflicting interests, conflicting cultures and conflicting work attitudes. One side will resent the other, and instead of new booming towns, there will be wastage and empty buildings.
The current system is better, where a country simply sends its people to build infrastructure and then walks away. Perhaps even build the entire physical infrstructure and buildings of a city, but the actual management has to be separate, I'd think.