Dead religions are usually pretty safe. Aztec or Incan deities would be cool. And you could probably go nuts with Japanese mythology without too much trouble - as vigorously and cheerfully as anime, manga and Japanese gaming maul Western mythology, it'd be really, really hard to argue that it's any great insult or imbalance of power for a Western author to do it right back.
But fictional has its own merits to be sure. I would really love to see this old plot thread picked up again, frex.