The excellent economist Paul Romer advocates "charter cities" in this article in Prospect Magazine. The idea is simple enough in theory. Wealthy developed countries (DCs) can assist development efforts in less developed countries (LDCs) by creating charter cities in LDCs, which for some finite period of time would be under the jurisdiction of DCs. The presumption is that political control by DCs would mean better governance, which would promote economic development. The historical model Romer has in mind is Hong Kong, which under British dominion became a wealthy hub of development in an otherwise poor and under-developed part of the world.
The idea is fascinating and surely worth experimenting with - especially given the failure of traditional development aid and lack of new ideas on that front - but I can already hear the catcalls of "neo-imperlialism"