If you haven't checked out the new GlassBox engine, you should . It's an interesting concept. It does make you wonder though how processor intensive this is when you start incorporating multiple elements from a city, such as traffic, people, resources going back and forth from building to building, natural resources, works, and utilities. I'm starting to wonder if my computer that I have right now is even powerful enough, especially if your city grows into a full scale metropolis.
Most of the recent games are a bit overwhelming for my poor computer. It's getting old. It has one of the first duocores in it. (Athalon 4400.) I've gotten used to my herky jerky Sims.
Sounds like a good excuse to upgrade I guess. ;] I do love the idea though, no matter how much processing power it uses. I wonder how many threads the game will actually use.