Italian site 4news claims that Microsoft and 343 Industries are working on a HD remake of the first Halo: Combat Evolved. It's not supposed to be a separate game, instead it's some of the first levels that will be included as part of upcoming Halo 4 - which 4news claims is supposed to be launched in 2012.
Good, with Halo: Reach out it was only a matter of time before the Halo 4 rumors started in earnest...