As announced in the Google I/O 2014 keynote, the Android “L” Preview factory images for Nexus 5 and Nexus 7 (2013) Wi-Fi are released to the public. And yes you read that right, no Android “L” Preview factory images for Nexus 4 are released (it was not mentioned during the I/O keynote too).
Keep in mind before proceeding to download these Android L factory images that this is a preview version of the Android system image and you should download it only if you are a developer.This Android L preview Factory image is not a stable release, and may contain errors and defects that can result in damage to your computer systems, devices, and data. So use it at your own risk.
If you own one of the devices i.e Nexus 5 or Nexus 7 (2013) Wi-Fi and a developer or a enthusiasts who loves to try new things on his Android device, you can download theses images here.
We would love to hear some feedback if you decide to give it a try and install it.