Made this neat stretchy bracelet by loading up the Bowden on the Ultimaker with short chunks of colorFabb PLA/PHA and ninjaFlex. Chunky 0.8mm nozzle and 0.3mm steps. Pretty neat result.
Aside from looking cool, the flexibility is a nice balance between the relative stiffness of PLA/PHA and the high flexiblity of ninjaflex. Having the ninja in short lengths sandwiched between hard PLA makes it more pushable than a bowden full of ninja flex. Layer bonds between the different materials are strong enough for a bracelet, but probably not for anything with much shear or tensile loading.
Design: http://www.thingiverse.com/thing:293413
Looks great, would be interesting how it feels and react… How does the flex and normal PLA work together?
This one is actually PLA/PHA (pink and orange) and ninjaflex (black). The bond between them is quite weak (ninja and PLA might actually do OK as supports for each other). I imagine if it was mixed flex PLA and another PLA the bond would be much stronger.
I just ran a few more of these mixing filled PLAs with straight PLAs. I’m most excited about the bronzefill/woodfill combo. I’m hoping that the bronze polish doesn’t soak into the wood too much because I want to stain and seal after polishing.
thanks a lot for the detailled response! have fun testing, i’ll watch your results 
