This is using modaco's deodexed SystemUI. Flash this zip in recovery:

TransparentStatusbar-GNex_MCR-signed.zip

In this apk, I've added a statusbar_background.9.png in the drawable-xhdpi folder. For those who wish to change the opacity level, you can alter that png (just make sure you don't disturb the 9 patch lines). There's still some experimenting I'd like to do, particularly with large screen devices, to make sure it's thoroughly integrated correctly, but this is decent for now.

As far as instructions, I'll have to cover those instructions later when I have a some time to make a thorough post.