This is a slightly more aggressive version of my first attempt http://www.thingiverse.com/thing:1512362
Printed these on a FF Creator Pro in NinjaFlex at 70mm/s with the Flexion Extruder
I used the full build plate for this, but it was still a bit tight on a size 10 shoe. A lower durometer filament would also be nice (Be sure to tell NinjaTek if you also would like the ability to print in softer materials). The Flexion can easily print as low as 60A durometer...we're just waiting on them to put the material on the market.
You can get the mend plates and the chains at Home Depot for a few $
Happy printing....of worthwhile/functional things...
PS> Take them off before you walk across your hardwood floor!!!