reprap cube - speed optimized, big built aerea, replicating

This in another reprap derivat printer. The main idea to built it was to get a printer which is fast and has lots of space to build things. The x and y axis work with an etch-a-sketch kind of mechanism with two belts. The z axis is driven by 3 thread rods. The main frame is a cube built of 20mm extruded aluminium profile. my frame is 400x400x400 but this can be scaled as you like.
The extruder i designed for the printer is that one: http://www.thingiverse.com/thing:14311 and the electronics i use are these: http://www.thingiverse.com/thing:6480
The pulleys were rendere with the scad script by droftarts: http://www.thingiverse.com/thing:16627 thanks a lot for that. Except for the frame,the rods and some standard parts, all parts are printed. (The edge-connecters could be printed too, this can be extended here)
UPDATE: i connected the stepper drivers and the other electronix for the axis today and did some first axis-tests. There is a video on vimeo:
https://vimeo.com/50614766