pic: Ahhhh, that's better.

[DampRobot]

This might just be me being blind, but is the way those idler gears rotate just a frictional bearing between an aluminium round shaft and the hex on the gear?

Just curious, I'm happy to take your experience at face value, but did you happen to run any tests of this drive train compared to a similarly geared belt or chain one, in terms of efficiency or speed? I'm a big believer in chain/belt drives, but I can certainly see the advantages to this type of drive, especially if the efficiency is as high as other drive types.

Any plans for integrating some sort of reduction into those idler gears? You could probably make those side rails with a slick little integrated drive gearbox. It would be almost like 610's setup, but with gears instead of chain.