Ok, after googling around I found the answer. It's quite simple. The answer is a combination of the two answers above plus a few more. Open a Terminal and type the following command:

sudo cp -rf .config/ .gconf/ .gconfd/ .gnome2/ /etc/skel/

That's it. Now all the changes will appear for the new user. This worked for me. I tested the changes by creating a new user.

Note that this will not change the launchers for already existing users, just for newly created users.

11.10

There is a way to make the icons smaller, however the icons are surrounded by backlit that's always 54x54 px and you can't shrink that, it's hard coded. What you can do is this: