One of the things that makes this set unique is the automated process that Inkscape has enabled: first, I draw a single icon and set up some colours.
Then, using a bunch of python scripts and Inkscape extensions I've written, it is converted into four different sizes, pixel grid aligned at those sizes (including multiple nodes and straight lines in complex shapes), has some effects applied (adjusted for every size), converted into two additional icon styles, and saved as PNG. It absolutely blows me away that this is possible, and really shows what can be done with open standards and OSS.
Here they are:

And here's a gallery with various screenshots: http://imgur.com/a/ez7QI
They're available for free over here on Google Play: https://play.google.com/store/search?q=pub:Etched%20Design
And here's a thread on XDA-Developers for technical support/icon requests etc: http://forum.xda-developers.com/showthread.php?t=2463188
It's still very much in development, so I'm interested in hearing any technical or artistic critique that any of you have!