Dimensions of Mindstorms NXT pieces
Just measured them myself. Some of the dimensions might be just a little bit off, but I hope this suffices:

NXT:

Length: 111 mm

Width: ~71.7 mm

Height: 40 mm (extra 8 mm if you have a rechargeable battery installed)

Motor:

Length: ~105 mm

Width: 40 mm

Height: ~45 mm

Ultra-sonic Sensor:

Length: 44 mm

Width: 44 mm

Height: 30 mm

Generic Sensor:

Length: 44 mm

Width: 22 mm

Height: 30 mm

If it's a touch sensor and the button is not pressed, then it's 47 mm long.

Again, some of these may be a bit off since some dimensions were difficult to properly measure with the ruler I was using due to the geometry of some of the pieces. If you want a more accurate and precise measurement, someone else might be better equipped to answer your question.