This is how you "force an update" on a Galaxy Nexus, this is what they did for the 4.0.4 update
Source - http://phandroid.com/2012/06/02/force-android-4-0-4-ota-on-the-verizon-galaxy-nexus-no-more-waiting/Here is what you have to do:
- Go to settings>Apps>All
- Tap Google Services Framework
- Tap on Clear Data and then Force Stop
- Go to About Settings>About Phone>Check for Updates
Anyone want to try that out? It won't work the first time I know that, it might take 5-10 cycling those steps to get it.