Update: now tested, worked great as it was!
Still untested design for mounting 1/8" pneumatic push fit connectors. The design is based on hugokernel's http://www.thingiverse.com/thing:177209 but was heavily modified (stripped down, some refined measurements and simplifications). I also modified the thread library, because I was unsure if the pitch was correctly calculated (may work without modification). I played around with hulls to achieve structural stiffness, hope you like it :)
Update: introduced a correction factor to make the threading a perfect fit. So the 1/8" connection works now, last thing waiting for testing are the M3 hole distances, the diameters are also perfectly fitting.