Very cool concept.  I'd be interested in joining.  Do you have sort of outlines for what races of monster might or might not be acceptable?

Vampire?
Werewolf?
Lovecraftian Detective?
Hills Have Eyes type cannibal?
Undead Cowboy?
Gamblers with debts to demons?

I have a rather specific idea myself which is sort of a Native American version of a vampire.

You might look at the Deadlands Tabletop Game for some inspiration.  Similar concepts although explicitly American.

If you go to the Stuff I Did link in my bio, in the second post there there should be a link to a Deadlands thread I started some time ago and a short Campfire Story