Still on the Halloween costume search...

How about the Librarian as a costume?

"And here's the most heroic character in Terry Pratchett's "Discworld" book. A librarian in a magic library gets turned into an orangutan, but declined any well-meaning attempts to change him back".

From: http://elephantmarch.blogspot.com/2008_05_01_archive.html

Halloween costume search discovers "The Incredible Plush Discworld"

Browsing the web for Halloween costumes (yes, cutting it a little fine this year).

Thinking of Terry Pratchett's Discworld characters and found:

Brighid Hurtubise and the Incredible Plush Discworld

Daily Illuminator: The Incredible Plush Discworld
Not sure the four of us can exactly go as this, but Discworld awesomeness!