Spool Holder / Tray for Prusa i3 MK2

When I broke my Prusa's original spool holder (which I was never really fond of), I went looking for a replacement and found this one http://www.thingiverse.com/thing:1940105 , designed by Area51. The spool holder is decent, but what really impressed me was the way it clipped on to the Z-frame. Very easy to put on and take off, and rock-solid stable. A great clip design. So i stole it for this Thing.

I've always preferred spool holders that sit on the bench. I've printed several rim-rol