@RickMerritt: I am sure this is a typo (slide 9):
"STMicroelectronics LIS331DLH six-axis accelerometer." It is a 3-axis part; for Mechanics purist, the additional three degrees of freedom (DOF) represent rotations (angular / tilt sensing DOF's) that are possible to be measured if you use a triad of accelerometers at the origin and two orthogonal ones along each axis (i.e., Z & Y along X, X & Y along Z, etc.).
Great dissection nonetheless!
As always, Apple has done a great job on mechanical design. The assembly (dissemble) of the units is so straightforward. What amazed me is the weight reduction. There are so few components; majority of the weight is coming from the battery. The analysis indicates Apple has push the weight to the limit. What else can Apple to do increase the battery life? Reducing power consumption from the CPU and screen?