I love these styles of backgrounds, and would be very interested if you have a gallery. I personally use blender to generate backgrounds in this style[1]. I keep putting off exploring this tool because I have difficulty parsing the syntax.
I used very different techniques for each of them, sorry but I didn't base these on any tutorial. I made each of them after I had learned something about blender I wanted to try, or I had an idea I thought I could get away with.
I wanted to play around with more complex texture mapping and uv projection for the first one, I tested out a way to use the array modifier to make Escher style tiles, I wanted to test the ways I could make flat facets with greater than 3 sides using the new decimate options, render and rig an STL from openSCAD, or work with new wireframe options and use dupliverts, respectively.
It's heartening to know that other people out there share my sense of aesthetic, though!
1. http://imgur.com/a/AaHGw