Dianna Agron is the epitome of perfection.
Quinntology.
Last summer Bungie did say they were working on three distinct projects. The Mythic Map Pack, ODST, and now the recently revealed Halo: Reach. So, we could make guesses as to what it was going to be and such. I don't think they made that big of a deal about it because it is going to be released in the fall of 2010 and ODST is being released in the fall of 2009. However, I wouldn't make the assumption that they haven't gotten very far on Halo: Reach. Why? Because there will be a beta with ODST.