The problem with this idea is that while strength in one direction may improve with the fiber reinforcement, that's the direction that this sort of print is strongest in anyway. I don't see it making the part any stronger across the laminations, where one layer of plastic lays across another. This is the direction (vertical, as the part is built) in which these parts are already much weaker than solid plastic, and the fiber won't help.

Andrew Werby
www.computersculpture.com