regarding the DL Superdrive
I'm pretty sure that the inclusion of the DL Superdrive has more to do with where the drive is placed (vertically speaking) than how much extra space is there since its wider. Its still 1" thin. Which is impressive i might add... but observe where the drive sits on the face of the computer - along the top, whereas on the 15" its in the middle (parallel with the latch button). The placement of this i think is what allowed them to have the DL. I dont know why they didnt do it like this in the 15" but i will say the aesthetics of the 15" drive look a little better with the burner slot flush in the middle. I bet they figured, "well if we keep the 17" design the same that means, less design work and more time to focus on other things, it means we can keep the DL burner for now, and it gives us a little more flexibility in the future for cramming in other drives i.e. BluRay or faster DL dvd burners that have currently unforseen thicknesses." Keep in mind too that the thinness of the 15" doesnt negate the ability for a DL drive, but just "not yet". I heard somewhere that they'd be thing enough by the summer time, so i guess in time for the Merom Rev. Don't know how credible this is though. In the 15" powerbook they had some extra computer thickness to allow for the thicker drive.. but in the thinner 17" powerbook, the drive slot was placed along the top of the front of the laptop to allow for the buner as thick as the DL superdrive.
just my opinion...
GOod job though.. keep 'em rollin