I actually only have it pseudo-rigged: each section (torso, shoulder, upper arm, lower arm, etc) is a separate object with the pivot point for each at the point where it should pivot. There aren't any bones, except in so far as each object is its own bone. With a well-laid out hierarchy, that's enough, skinning just gets in the way.
The downside to doing that is that axes are generally fine, but often have problems with curves between keyframes due to unexpected orientations. I *think* I've got this one sorted out fine for some animation, but haven't yet had time to test it out.
The lack of time is the main slow down here; I've picked up a small contract doing some paid 3d modelling, and that is eating up time that could be used modelling BattleMechs. Clearly, my priorities aren't straight

. At least its paying for a copy of 3D-Coat.