if you disable all the boot animations, you will see the word "android" with a nice effect as boot animation(this is the stock one), instead I replaced it with the words "Galaxy Nexus" and made the effect more dark(almost black&white).
Yes you have to replace the images in framework. it's really easy, as it doesn't need decompiling. But one has to replace the images, which isn't as easy as pasting a zip into a folder
I attached a zipthemer file, I hope it works, I' m not expert in zipthemer(please choose to make undo file in zipthemer)
you can see a video with BAD quality here http://www.youtube.com/watch?v=6qQyfPUhMto&feature=youtu.be
Ok cool, cheers buddy, I have added this to the 'Boot Modifications' section of the top post:
If you are a fan of the oldskool 'android' boot animation then you might want to check out this great set of files that replace your boot animation with a custom Galaxy Nexus version created by nikosrs4
Galaxy Nexus boot files | Further Info | Video