check out the FAQ at:

http://db.gamefaqs.com/console/ps2/f...night_2004.txt

this has a list of CABs that people made of fighters missing from the game.

it has the following CABs:
Mike Tyson
Naseem Hamed
Wladimir Klitscko
David Tua
Zab Judah
Oscar De La Hoya
Kassim “The Dream” Ouma
Diego Corrales
Manny Pacquiao
Cory Spinks
George Foreman
Thomas Hearns
Marvin Haggler
Jack Dempsey
Joe Mesi
Andrew Golota
Kostya Tszyu
Julio Cesar Gonzalez