Hi.
I have been working on a 3D printable palletizer robot arm for about a year now. I am at the third iteration now, and it is quite nice now (I think at least).
There is a short description here:
http://www.thingiverse.com/thing:1774473
But the files are on github (a link is in the description above). I have also put a lot of effort into an assembly manual which is also available there.
The design is released under a CC BY-NC-SA license.
Best regards,
Mogens