Current rumors point to an Apple event on October 14th that is supposed to bring us new MacBook notebooks. Rumors about the surfaced MacBook Brick are now pinned on a new manufacturing process that would put Apple into the manufacturing of MacBooks. In particular it is speculated Apple would be producing MacBook cases from a single piece of Aluminum - the so called Brick.
This rumor has wild implications as it suggests that Apple is having a manufacturing plant secretly built somewhere to make these.
Carving a notebook case from a single piece of metal with lasers would of course give designers a lot of freedom and it is not that easy to replicate such a process, if indeed Apple has invented such a process to be cost effective.
More in-depth speculations on the MacBook Brick can be found on 9 to 5 Mac.