Android's virtual navigation buttons, introduced in Honeycomb and expanded in Ice Cream Sandwich, have been something of a polarizing subject. While plenty of users appreciate the flexibility and aesthetic options they provide, others miss the physical feedback of real buttons, or would rather use the full size of the massive displays on current high-end phones. If you're a Galaxy Nexus owner who falls into the latter camp, you're in luck: XDA member "mrx8836350" (catchy!) has developed a method for banishing the navigation buttons altogether.
The tweak requires modifying your phone's Framework.res file, and replacing the original with the modified version. This isn't for the faint of heart, which is why the poster has supplied flashable ZIP files for the stock GSM Galaxy Nexus, Android Open Kang Project and Apex ROMs. Check out the source link for full instructions. For those who are wondering, the Nexus in its standard form uses true fullscreen only for properly-coded video apps like YouTube; most games and image viewers are stuck with grayed-out versions of the standard navigation buttons.
Check it out:
Of course, once you've disabled your navigation buttons, Android can get a little hard to... navigate. It's a good thing that there's already solutions for modded tablets without full Android buttons, like the Nook Color and HP TouchPad. Download Button Savior or Virtual Button Bar from the Android Market to compensate. As always, mod at your own risk, and make a Nandroid backup before trying anything fancy.