Very simple adapter for the gBeam: Mount you old minolta-bayonet-connector. It works very well for me. Just bend it a bit open, attach it to the lens and screw it in. Update: In the meantime universalist himself published a compilation of different SLR-Lens-Adapters: http://www.thingiverse.com/thing:1062085 Thy them first!Maybe you have to add support - I printed mine without but had to clean the inner ring a bit. I added the freecad-file so you can change it if you need to.