Create a game scene mockup

Need a screen design for promotion of a game under development. The theme of the game is "Business Wars". These are the requirements: 1. The scene should depict a bustling metropolis in the center with outlying areas much less developed. The feel of the scene should be like a snapshot of a busy city. 2. There should be people (some white collar, some blue collar, doctors, lawyers, waiters etc) within the scene, on the streets, inside building windows etc. 3. There should be assorted vehicles on the streets, and assorted street signs, street vendors, trees, pets, etc - everything that is associated with a city. 4. Outlying areas should have farms, factories etc, sparsely populated. 5. The style should be light / cartoon style, but for a serious game. 6. There should be some diversity in the images. Eg. dont repeat just a single building for the whole scene. 7. There should be 4 company buildings in the mockup that represent the players. You can use any name / design element to give the feel that its a player owned company 8. Deliverables are high quality PNG image and the PSD file with the scene devided into elements and atleast 3 layers (background, buildings, rest).