Small possibility but looks pretty professional and *official*. Also been rumored for weeks. [/gut report]
Also, Webhallen is a excellent site, been around for a longer time (I know you know that but for the rest).
I would think they would want to announce this officially very soon. If they are looking to pull people away from buying the Xbox 360 version, especially if the person already owns an Xbox 360, they don't want too drop the bomb to close to it's release. The price is too high for an impulse buy. Money will have to be saved or allocated for such a big purchase.