Japan and Korea will be in typhoon season so the WC would have to start early like in 2002. So I don't think its going back to the far east.
Mexico could prob do it but they've had 2 and the weather won't be too nice.
I think if Germany is out it will be between the US, Spain and England (I wonder what would happen in England doesn't qualify though would someone get booted).
Others who could do it.
Russia - Not great stadiums but could throw a buy off Fifa suits. Plus good weather for football in the summer
Netherlands - though the country is already crowded they have the facilites though no real large stadiums
Italy
Australia - it would stay in the lower hemisphere
Though actually I can't really see the games not being played in South Africa. Really what do you need? A patch of grass a ball, a couple goals and some bleacher seats. Who cares if John Terry has ride a bus on a dirt road 100miles to a stadium and has to hang his clothes on a nail in the locker room? The millionaries can stay home if they don't like it. The places would still all sell out.