border said:Didn't they explicitly say that this was not going to be a Rock Band game, that it was its own unique musical journey? What happened?
They did indeed explicitly say that: http://www.boston.com/business/ticker/2008/10/harmonix_will_w.html
LoPiccolo, the Harmonix vice president, added that while the Beatles game will not be branded as a Rock Band game, it will be similar to Rock Band in some respects; it will also have new features specifically developed for the Beatles' music.
I'm guessing that they decided that branding it with the Rock Band name was good for business.