Google is making the best of allowing enthusiasts and 3rd-party developers early access to the next release of Android, and the result will be a less buggy release when L finally hits the grand stage. While new issues are reported each day, there's a lot of progress showing up on the Issue Tracker. Just yesterday, a burst of 18 bugs were marked as 'fixed,' following a 2-week gap without any obvious activity.
Nexus 4 owners, don't lose hope. Though your 2012 Google phone was cruelly looked over for the developer preview builds of Android L (along with everything that wasn't a Nexus 7 2013 or Nexus 5), sharp-eyed Google+ users have spotted two different Google employees posting on the Chromium section of code.google.com claiming to use the Nexus 4 with Android L. Check out this entry from a contributor with a Chromium.org email address, explicitly using the "LRW52G" build of Android on his or her N4.
It's been over two months since Google gave Nexus 5 and Nexus 7 owners a chance to tinker with the upcoming L release of Android, in what has been the biggest beta test in Android's short history. With all of us waiting on a release sometime in the fourth quarter of 2014, it's gratifying to know that the powers that be are hard at work getting Android L ready for primetime.
Thanks again to the venerable JBQ of Google, the unmodified factory image of Android 4.0.4 for the Nexus S 4G (sojus, Android 4.0.4 IMM76D) is now available here. As JBQ states on Google+, this image is for those among you who have flashed to custom versions of AOSP and want to get back to factory state. No, by the way, there's still no word on an OTA update yet.
As with all the others, the factory images are available on the Factory Images for Nexus Devices page.