For my running animation I wanted to try and do kind of what I did with my Idle animation, just start with one part and build it up to a complete animation using the principles of animation and my intuition which meant not using any particular reference, but I did use a standard running reference as an initial guide to just get the basic running frame set so that I could then tweak balance and squash and stretch and things later with a good foundation.
http://www.youtube.com/watch?NR=1&v=lCpotGr0TB4&feature=fvwp
http://www.youtube.com/watch?v=PUOhwlcYzcc
Here is the completed animation, I'm very happy with the result. I had a few problems at the start but I managed to whittle them down over time. I had to move all of the key-frames down at first because they were all too far away and stretched out the the animation was really slow, that was an easy fix and mostly a result of me going in blind in the initial stages of setting up the foundation running cycle.
http://www.youtube.com/watch?v=9ofaULoUq4w
This is just a video showing my progress, it start out quite late because I just made this video using my available save-states at the end, and I forgot to save at all for quite a while up until I had a decent looking running animation foundation.