Gentlemen,
I would be a bit leery of the belt tension as shown.
There is a significant amount of slack (as shown by the red lines) and I would be concerned about the hysteresis (IE: backlash or play) and the resulting wave form induced in the belt at the period of dynamic loading and unloading. This wave can allow the belt to climb the teeth and walk off the pulley without very large flanges to keep the belt in position. (I think this is Mark's concern.)
Also one must remember that more energy is produced during the loading and unloading period with a slack belt due to internal friction produced by the wave form and that energy must go somewhere, it is dissipated or "lost" as heat. This "extra heat" can decrease belt tooth life considerably.
For this belt configuration Gates recommends the Static Tension per strand to be from 23 to 26 lbs. See:
http://PowerGrip Calculator
OK. All of the warnings aside..........Nice looking system.