Digital Photography Review has published an article on the Canon EOS 5D that includes 28 photographs taken on the streets of London with a pre-production body mated to an EF 24-105 f/4L IS USM or EF 100-400mm f/4.5-5.6L IS USM.
More here:
Rob Galbraith DPI: "Canon EOS 5D Hands-on preview" posted at dpreview