Hey sorry to throw another one in the mix but we just released our sled. This was my pet project so I am really excited about it. I pulled 450 lbs on it two weeks ago. You can see it at www.cfffit.com/index.php/CFF-Sled
You can watch an overview of it here http://www.youtube.com/watch?v=rk0KteHtPZ8
(wfs). This is the first of a several vids about it. I am working on the video when we were pulling the heavy weight on it.