I did a unit size comparison, using images that show more than one unit, some available data on unit sizes that is available, and some guessing based on cinematics, and was able to do this:
Yeah, i know it looks like they're all suspects of a crime. I wouldn't like to be the police officer that arrested them
Way Old image: http://img341.imageshack.us/img341/1...aos3screen.jpg
Previous image: http://img687.imageshack.us/img687/4...amaos4gray.jpg
Changes: used Immortal instead of Dragoon, Viking is bigger, Ultralisk is smaller, Queen is bigger.
Changes: Immortal 1m taller (looked at portrait), changed Viking for Wyrm and made it 2m taller (it was the Wyrm's concept, anyways).