3D modeling, rendering needed

I am looking for someone who has great experience in 3D modelling and rendering realistic scenes. I will need you to use existing 3D models found on-line, modify them slightly and render them. You must: 1. Have some existing 3D models of men and women of various ages. 2. Be able to change these 3D models skin color, facial features, hair and eye collor. 3. Render these models in the most realistic rendering engine. 4. Provide me with the source files and the resulting images. 5. Be able to work on similar projects in future. Please contact with samples of rendered realistic 3D portraits or body shots.