Fingers crossed that it's merely a case of all the component ducks being lined up in a row. They'll want to launch with latest Xeon+latest AMD graphics, and not risk a repeat of the Power Mac G4 'Yikes' situation, or launching with one set of components, then doing an update two or three months later because the ones they wanted were finally available. After all this time, it's got to be right, or they might as well not have bothered.