ZoopremeCourt.org combines two things I adore–the Supreme Court and zoo animals!
What about Antonin Skunkila, Anthony Toucannedy, Clarence Thomouse, Samuel Owlito, and Elena Kangaroo?
For old school Justices, check out Otter Stewart, Byron Great White, and Arthur Goldbearg
Update: A few of my own:
John Blue Jay, Badger Taney, John Marshall Marlin, Rufus Woodpecker, Oliver Wombat Holmes, Robert Jackrabbitson