I agree that it is too soon to see an iMac upgrade, no processor bumps, no size bumps, no new case design w/o new cpu. while the mini will most likely get c2d, the mac pros may not see dual-quad cores until late jan or feb. mwsf is not typically a pro machine expo.
so what does that leave for mwsf other than full-screen iPods, iTV, iPhone and Leopard release date?... and possibly displays..
I think it is the perfect opportunity for the Mac Pro Mini or Mac Pro Jr. Return of the Cube, Headless iMac, whatever else you want to call it.
I don't think Apple will do mwsf without a significant computer announcement, and I think the full-screen iPods are delayed.
On a sidenote, I'd be very interested to see a black or silver (ACD style) iMac released. But then a black iMac, c2d Minis, iPhones and a Leopard and iTV release date is a little weak for a macworld. Though more is overly optimistic.
Don't forget there will be iLife '07 for steve to eat up some keynote time with.