Now that would be fun to go for! On chieftain you could KO most civs and limit the progress of the remaining one with a constant war. I think that the human player could keep the AI down to a single town and if it did build a second city you can decide which one to destroy. Lux and strat colonies could be easily protected, research would be very quick for the human and so the AI would be behind on territory, happy and content citizens for so long that it could be done. I'm sure the elite players could manage that on a much higher level. The more I think about this, the more I think that it could be done with relative ease on the lowest levels.