In an interview with Kotaku the developers have told that Halo Reach might actually have Natal integrated in to the system. Studio head Harold Ryan said it could be used in “Reach.” “I absolutely think ‘Reach’ could be enabled with it,” he said.
This is not a confirmation, although Microsoft have been pushing Project Natal as the next big thing, so it will be no surprise that it might be implemented in one of their premium games this generation.