PhD's post is the most reasonable prediction in my opinion, and it's also what I had expected.
But I don't understand delaying the reveal until November and then trying to undo it by controlled leaking.
Maybe they didn't want to be like "Hello again. The new flagship mac will ship with two midrange cards ($200 retail) with 40% less tflops than Nvidia's offerings, it will be $4,000"... at least in front of a live audience. Don't worry, I'm sure they'll just do what they did with the radeon 280 and call it a D900. I'm still not convinced it's going to happen.