Argonor: maybe, if you're planning on using .45 Adventures, the different parties could all be "searching" for the werewolf, but in reality one of them is hiding the creature. But none of the players knows which party has the werewolf (not even the one that has it). Then find some sort of mechanism for figuring out who it is during the game ... hmm, just some food for thought ...
Don't start holding your breath yet it my little company Fiendish Fabrications has been working on a game something along these lines for a while now. Play test will start soon and the game
should be released by the end of the year. The working title is
After Dark.