I needed wire guides to make a project look more clean. I designed my own (less than $.05 in plastic and six minutes print time) and can print them in colors and sizes to suit my needs.
In this instructable, I will show how I used Autodesk 123D (free) to design a part.
What I do is "start with a box" and remove everything that is not a wire guide.
Follow along--you'll see that it's easy.
Design files available here:http://www.thingiverse.com/thing:42894