It seems that the Nexus Q, while still not officially re-available in the Play Store, is apparently anything but forgotten. The device – which is codenamed steelhead – just got its first official CyanogenMod 10.1 nightly build. Neat-o.
It could oftentimes be unstable and not properly tested, lacking any changelogs, but eventually evolving into alphas, betas, release candidates, and finally stable releases.
Installing this build works basically the same as other Nexus devices: boot into recovery and flash.