Hi Ted,

This is an interesting topic, and I like the idea of a blog to get the interested people to contribute data (I won't be able to do so personally though because I don't have a treadmill ;-) ). I am also looking for spatio-temporal data, but in gait, not running.
At some point during your investigations, I have the feeling you may be tempted to calculate the correlation between speed vs cadence, or normalised speed vs normalised cadence. You may be interested to take a look at an article we recently published on this topic.
It would also be interesting to investigate if dimensionless normalisation effectively remove the effect of leg length in the running data, or if there are conflicting results as we 'discovered' in gait.

Good luck,