I've just ordered a 15" with all the extra options, so I freaked when I saw this: my wife uses one of the big Sonys, and the display is awesome. However, the display is also very thick, nearly 3x that of the powerbook. My guess is that Apple would have real difficulty fitting that display into the current form factor, and that's why they dropped the idea. After all, why introduce a new case size just as the product's coming to end of life?
Fwiw, I think Apple are covering their butts here: if they can't get the G5 ready for a MWSF launch (which I doubt they will) then they have the option of going HD to keep the market going. It will also allow them to beta-test all the new display bugs on an existing platform, and get rid of the inevitable white spots and keyboard marks in that revision.
Then they can launch a G5 with no display faults, which will be nice. G5 Rev A users can just worry about the knackered hinges, electric shocks, unworkable battery life, jets of boiling liquid coolant flying out, scalded laps, etc etc etc
