I would love to help with this
Well I am trying to make some designs at Cinema 4D (if you know it...). As I said I don't have a 3D Printer and I don't know what files the need, but after a search I found that Cinema 4D can also print in a 3D printer. I tried OpenSCAD as well, but I found Cinema 4D more user friendly :P

I would love to see some psp-style buttons on the gripper and, as I said, I would love to find out if it is possible to "connect" the gripper with the n900 with some magnets or any other way instead of using the parts that cover the battery...