I have not printed this yet, so I don't know if it will work. When I receive my Printrbot I'll try. Click "I made one!" if you make one! :)
Description from thing:19010
This is a tab for mounting 3mm glass to a 3D printer - four of these will be required, one for each corner. The holes are 3mm diameter, and designed for M3 bolts.
4x M3 bolts