When developers work as a team, nothing is impossible. Merely weeks after the Android L developer preview released, a sprightly collective over at XDA has managed to build a working ROM based on the preview for the aging Nexus 4.
Despite carrying a “beta” moniker, the updated ROM is miraculously free of the major issues that plagued its last release, the worst of which included non-functioning sensors and Bluetooth.
Root management apps work (so long as you use Koush’s Superuser), and minus instability inherent to Android L, the sailing seems smooth enough to use the build as a daily driver.
For installation instructions, refer to the XDA thread.
Note: If your home button quits working after install, do a full wipe before attempting to flash the ROM again.