Built the skeletal structure using NURBS spheres. Similar to the one in Autodesk Hyper-Realistic series. Played around with rigging up the scapulas, and pretty happy with the results. Managed to achieve a little "sliding around the rib-cage" effect. I will put up a video on that later.
Muscles built using a simple muscle plugin with 4 attachment points and volume preservation.
This is the test to make sure no muscles flip during motion, before I even start skinning them:
Next up, the skin deformation itself.