When the MSR-H01 is in it's normal standing pose, are the servos actively supporting it?
Yes... after all, Newtonian physics says SOMETHING must be. Depending on the posture there's a bit of math involved in figuring out exactly which servo is doing what, but it's all there.
Or, to put it another way, would (somehow) measuring the current in a servo's motor give an indication whether that leg was supporting the hexapod, or raised in the air?
Maybe... that's the interesting question. Clearly there is SOME information there, the question is whether it is repeatable and linear enough to be useful.
Anyway my little hexapod is now wending its way to me from Illinois (via UPS, not autonomously I'm afraid), Trossen just knocked $100 off the price of a MSR-H01 and that was enough to push me over the edge. My plan is to first build it "stock" with Matt's controller, then start modifying it. I already have some FSRs and an Openservo kit, all I need now is time. The "proprioception" approach is mechanically way easier than using FRSs, so it will be nice if it works.