One of the excellent developers, WugFresh, over on our very own, has developed a Nexus Root Toolkit (v1.5) for Nexus devices and it now includes the Nexus 7 too! It has an amazing array of features already, with unlocking, rooting, relocking, unrooting and more. Furthermore, the utility makes it very easy to do all these things. Here's a quick quote with a more detailed description,

VERSION 1.5 - This program contains all the files you need to unlock and root your device, or flash it back to stock and re-lock it. You can also use this program to backup/restore all your important data, flash zips, set file permissions, push and pull files, install apps, and much more! With the included file association options, you can perform tasks like flashing zips, installing apps, restoring android backup files, and flashing/booting img files with just a double click! This new version now supports all Nexus devices (including the Nexus 7 Tablet). To explain all the new features in more detail, I included a full help file with the program for your reference.
Head to the source link below to check out his amazing work! Thanks again WugFresh!