I think this is the last bit of concept art from my MechWarrior 4 days.
The original Cauldron Born didn't have any torso twist but we added a waist joint so the mech would fit in better with the other mechs and make full use of the shared skeletal animations. The posing on this sketch isn't all that great but I think the 3D model was pretty well visually balanced.
I loved this mech, it was the one mech in mw4 that I found to be virtually impossible to kill in under a minute. I used to fight in this thing and usually wound up with absolutely no weapons, a disabled leg, both arms and side torsos thoroughly destroyed, and still lurching around like a zombie because all the people I was playing back then couldn't hit the center torso, and didn't have the brains to take out it's legs. Truly a mech that lived up to it's reputation. Also, toss a few LRM 15s on it, and max out the engine, and you had a pretty awesome missile boat.