There are lots of filament choices out there for your (hobbyist class) 3D Printer, but a flexible one isn’t one of them. Earlier we saw you could make flexible links using sugru but full on printing would be a more optimal solution.
A little more digging shows a recent blog post on the makerbot web site referring to an entire dress they printed on the Replicator 2 (don’t kid yourself, it still took a long time!). It looks like the filament contains polyester which allows it to move after extruded.
They currently have a stub on the makerbot store which makes me believe they are pretty close to getting this to market. Can’t wait.