Yeah too bad that Lion osx is not customizable as used to be even when it has more interaction with end users and a recreated interface with gestures and all of that, seemingly designers found restrictions so they can't customize everything however there are some apps which makes you're desktop barely different you should google it, and about the icons someone shared them before and here you go the [link] (ICN's format ) Enjoy!
try theme Adwaita Cupertino.. is a perfect theme.. you can find this theme on gnome-look site
I'm highly curious as to where those dock icons came from.