We already reported that, Android L was being tested for the Nexus 4, and now we have more good new.
Google has confirmed that Android L will be arriving on the Nexus 4, 10 and Nexus 7 (2012), by posting developer preview source code for the devices, at the Android Open Source Project (AOSP).
Here are the links to the AOSP sources for the devices:
However, they have not released a system image, and the sources they have posted are incomplete, so users will have to wait for a while for it to arrive. The factory images will be published at the the official page, when they are available.