A newer version with a screw-on lamp chassis can be found here: http://www.thingiverse.com/thing:2094215
Highres version of http://www.thingiverse.com/thing:1922547
This one uses 85x85 pixels instead of 55x55, but also is bigger. It is 15 cm in diameter, it barely fits on the buildplate of my Flashforge Creator Pro. You could change the radius in the Customizer, but if you decrease it it will probably not slice anymore.
All parts are printed at 100%. I maxed out resolution for the given diameter, so it is still sliceable in Simplify3D. Other slicers are able to scale it down, but you may get issues with very thin walls if you go too low.