demo file can be downloaded at http://www.coreyross3d.com/blog/2015/8/29/quadruped-rigging-series-part-2
In this video, I go over quadruped hind leg set up using a techniques that involves two overlapping IK solvers.
IMPORTANT: Although i never mention it in the video, make sure you are always using object translate mode, that way the object stays in the correct plane and you can see the actually orientation.
You can learn more about my work at CoreyRoss3d.com
Look forward to Part 3, coming soon!