I've been looking at V-slot (which it looks like you're using) to do something similar (whenever I finally get around to building a printer ... ). Though, I want closer to 500mm in one axis, but the other measurements are more than sufficient for my needs. I was planning to go with a Z bed and XY head though - but with the right size extrusion it looks like an XYZ head is working fine for you.by biosehnsucht - Extruded Aluminum Frames