This is vertical x-axis for the MendelMax 1.5 (or any printer using the same rod distances). It is designed to host the 3-color Diamond Hotend (http://www.thingiverse.com/thing:720520) . There is also an provision for adding a SP90 servo mounting to use my Opto-Z-Probe (http://www.thingiverse.com/thing:263180). The probe will be attached at the rear - not disturbing any other component and almost invisible when retracted.
The whole thing is a remix of BLNorris "RustySpoon's Vertical X-Axis" (http://www.thingiverse.com/thing:12434) by adjusting everything for metric nuts, bolts, different nuts for the trapezoidal threaded 8mm rod and other slight modifications. So BLNorris great "RustySpoon" design works now for metrically addicted too!
The belt tensioner is a remix of xavan's "X carriage with belt tensioner" (http://www.thingiverse.com/thing:798169) - by the way a really great idea and very easy to use and extremely reliable! Thank you for sharing that idea, xavan!
Several M3-attachment holes for accesories for future modifications and add-ons (like for endstops, LED-lights,...) are already present.