Before giving the iPhone HD/iPhone 4G back to Apple, Gizmodo have done a tear-down and provided plenty of pictures of what they've found inside, including 50% of the space being taken up by the battery (which is not user-removable), and a drastically smaller, metal cased logic board. (Not to mention screws aplenty).
They didn't want to break open the board, so no word on whether it has an Apple A4 or related system-on-chip (SoC) like the iPad, or how much RAM is inside, and no word yet on NAND Flash storage capacity either.
(And yes, they did put it back together again, dozens and dozens of screws and all).
Anyone see anything else interesting in the parts?