A Portable Icon Packager?

You know something that changes all the icons on the system?
One that can run without admin privileges.
This would be useful for people that are under a limited account and are Vistaizing their Windows XP. I know something like this probably cannot be truly portable ( not writing files on hard drive or anything but the fact it is changing some system settings( the icons)).
And this would be great since I am Vistaizing my Winblows XP Pro.