BootUnlocker for Nexus Devices is available over at the Play Store as a free download, and will not work on Nexus 7.
(Source: BootUnlocker for Nexus Devices at Play Store)
How To Unlock Nexus 4 / 10, Galaxy Nexus Bootloader Without Fastboot
Posted on the 08 January 2013 by Skateroren @ProgramsAliveBootUnlocker for Nexus Devices is available over at the Play Store as a free download, and will not work on Nexus 7.
(Source: BootUnlocker for Nexus Devices at Play Store)