First, if you have not seen this clip yet, watch it. It is interested in both its form and its content.
Next, go read Danfung Dennis explanations of how it was shot and the gear he used. I like his Glidecam setup, looking at the picture you can see how many plates he used to balance the rig. Having played with a Glidecam 4000 balanced for the 7D, I can confirm how much weigth one has to put on this thing to make it stable.