Thanks, guys!
The legs I've made are a morph, and I just adjust the joint centers until they bend reasonably well, then fix any remaining problems with JCMs if necessary. The really long, delicate legs I did for the Deer characters didn't bend well without JCMs, but the beefy Werebeast legs seem to be fine without JCMs. One thing I would recommend when making a really extreme morph like digitigrade legs is to pay attention to where your groups are and making sure you keep the geometry fairly relaxed so it will still bend right with the weight maps on the figure, because you can't alter the weight mapping, in Studio at least. You can make injectable weight maps in Poser, but I still don't think it's best practice to alter them, otherwise third party conformers won't work well with the shape.
If you're rigging a conformer, you'll add a few bones from the donor figure, in the case of conforming legs, probably just the hip/chest/abdomen/pelvis bones. The bones for the legs themselves I would likely choose not to conform to the base figure's leg bones, because I think one of the major problems people had with the Creature Creator legs was that the thighs and shins conformed to M4/V4's legs. Maybe conform the thigh bones, it's a balance between keeping pose information from the base and having easily posed creature legs that don't have the base figure's rotation limits imposed on them (a lot of users don't realise they can turn limits off). So they would need to be named differently from the base figure's leg bones. Group your object with weight mapping in mind, and try to put your groups where you want the influence of the bones to be. When you're adding bones to a figure, I find it helps to visualize where the skeletal bones of the appendage would be, and place the joints there. Weight mapping is pretty darn easy in Studio. Start with the hip and fill the whole figure 100%, then go through each group and fill the corresponding weight map with 100%, copying the weight map from one axis and pasting it into the other two. I seem to recall that newer versions of Studio have a utility for that, but I'm just really used to doing it manually. From there, you just tweak things until you're happy, I tend to make generous use of the smooth brush.
Not exactly a comprehensive tutorial, more of a ramble. I have been thinking about maybe making some training material of some sort, like a video course. Though I don't pretend to be a master of the subject, I think I've got a few tricks up my sleeve that some people might find surprising and useful. ;-)
I was thinking I might try to convert part of my Philosopher's Egg catalogue to modern figures, as well as make some new ones like the Werebeast. The boar test seems to me to be quite promising. I'll have to test out a few projects to see whether there's a market for the rehashed characters, or if it's better to put my effort into new characters, though I have to say, I'm dangerously close to the brink of running out of animals to anthropomorphize on M4/V4 LOL!