Starting the "hit it to win it" database for mech killin'.
Also worth noting the armor amounts. Not my personal distributions, but max possible to find weakspots.
Post any you can like this and if it's ok with you guys, I'll copy here in order of weight class.
head
center torso
right torso
center torso rear
right torso rear
right leg
right arm


ATLAS, 100 ton















************************************


STALKER, 85 ton















************************************


AWESOME, 80 ton















************************************


CATAPHRACT, 70 ton















************************************


CATAPULT, 65 ton

Hate to break it to ya, but the sections displayed in the mech lab aren't the actual hit boxes in game. The "head" hit box for the Atlas is actually just it's left eye.

Someone posted them all in the MWO forums. I'll see if I can find it...

Here it is:

http://mwomercs.com/forums/topic/96395-guide-hit-box-localisation/

I think it's known to everyone that a cockpit shot means glass, not the general area. Still, the main panels are what I'm interested in and having a record of possible armor on each location. Going for cockpit shots all the time isn't realistic, especially on the move, but knowing the shape of the side torso is on a stalker (huge) vs a catapult (not so much, so aim for the nose from the side as part of the center torso) is handy. Shooting a stalker head on isn't a great idea, since it could hit any of 3 panels, but on a catapult it's a pretty safe bet it's all center torso. That's what I'm wanting to learn about on the other mechs I don't have time on.