Printrbot Simple Metal flex filament extruder arm derivative
Remixed from nmackes' v3 design (http://www.thingiverse.com/thing:951869).
I haven't printed with flexible filament yet with it (heh..) because I don't have a heated bed yet but plan use ABS to print thirdhorizon's extruder base (http://www.thingiverse.com/thing:403438).
Either way, this has worked great so far and the added handle has made it even better.