In Green Ronin's Advanced Bestiary they have a generic were template that as long as you have the regular creature (say a badger stats) you can make anything.
Technically, the Monster Manual has everything you need - the lycanthrope template, the dire badger (for small to large humanoids), and the standard badger (for tiny to medium humanoids). I don't recall if the Ravenloft werebadger is any different from that off-hand (and in any case, I only have the 3.0 version).