The measurements are interesting. It's pretty obvious the E-Mu and Massdrop cans are cut from very much the same cloth as the original Denon models. The Fostex TH900, TH900mk2, and TH610 are clearly different.
Crap, crap, crap. I loathed the sound of the original Denon. I'm getting very worried about my Ebonys now!
http://www.innerfidelity.com/content/survey-foster-443742-variants-measurements (stolen from the bass thread).