On a slightly related note, there is also The Invisible Library.
Mr. Brian Quinette, founder and curator of the original Invisible Library, writes: "The Invisible Library is a collection of books that only appear in other books. Within the library's catalog you will find imaginary books, pseudobiblia, artifictions, fabled tomes, libris phantastica, and all manner of books unwritten, unread, unpublished, and unfound."
The Library catalogues are here for the original library:
http://www.geocities.com/nodotus/hbi...lelibrary.html
And here for a far more complete catalogue:
http://www.geocities.com/jameshay.ge...leLibrary.html