Updated and renumbered. FinnishGuy, check out 4.1 and 4.1.1. Is that what you wanted?
markusf,
-SMAC has that feature and it's likely civ3 will also.
-Unhappiness due to overexpansion is already a feature of civ. One of Brian Reyold's requests was that players give reasons or specifics on how a suggestion would benefit/work in the game. Could you give me some reason why extra penalties/ no science 'til size 3 would be helpful to the game (IMHO most players would hate waiting for their 1st city to grow to size 3 before doing research)?
-So you'd like a list of the civs levels from 1 through 7? I can put that in.
-SMAC also has "governors" who will control your city production if you desire. IMHO leaving it to the AI is a bad decision. Let's hope for a better AI in civ3.
-Again, the eternal desire from every player: better AI. We'll have to wait and see.
-Check out the ECONOMICS/TRADE thread. Many suggestions of a similar vein are located within.