Removable Spool Holder for 2020 Misumi Aluminum Extrusion

UPDATE 11/29/16: I've been using this thing for nearly a year now, and it's held up great!

Ever since I built Jasonatepaint's awesome Aluminum Extrusion Ultimaker 2 a couple of months back, I've been using a Irwin quick-grip clamp on my desk as a spool holder... Not exactly elegant. I finally decided to actual fix this issue, so I popped open Thingiverse and started looking for 2020 extrusion spool holders. However, since part of what I love about this printer is it's portability and relativ