One question that's come up a few times is about limits attaching things together. For example,
Can you connect multiple bones and muscles to a fat/skin mesh, I was under the impression that you could only attach one zMesh to one surface?
There are absolutely no limits on adding attachments. Add them freely wherever you like. Every type of body (bone, tissue, cloth) can be attached to every other type of body. A body can have as many attachments on it as you so desire. Multiple attachments can be added between even the same two bodies. In any pair of body types, each can function as either the attachment source or target.
For example, one setup might have a muscle and two bones with each end of the muscle attached to a different bone with two different attachments. In the middle of the muscle another (sliding) attachment to one of the same bones keeps the tissue and bone in contact. In this setup, thre are 3 attachments on the tissue - one to one bone and two to another bone.