I made this costume for my (now ex) girlfriend for Halloween 2009. It is the movie version of the costume with the cut off finger tips but also has the book version of the scepter.
The main body is made from fleece. The tail is made from fake fur and contains a wire that keeps the end of the tail curled so it doesn't just hang limply. The whiskers are pipe cleaners and the crown is made from spray painted poster board.