This might have already been posted on here...but I've been paying around a bit and have managed to get rid of the navigation buttons at the bottom using the default launcher.
I used the FullScreen Toggle app posted over at XDA (http://forum.xda-developers.com/showthread.php?t=1497558) and then the Button Saviour app (https://play.google.com/store/apps/details?id=com.smart.swkey&hl=en)...works a treat so far.
Will test it for a couple of days and then see how it works on my Nexus 4 too.
I used the FullScreen Toggle app posted over at XDA (http://forum.xda-developers.com/showthread.php?t=1497558) and then the Button Saviour app (https://play.google.com/store/apps/details?id=com.smart.swkey&hl=en)...works a treat so far.
Will test it for a couple of days and then see how it works on my Nexus 4 too.