Challenges:

One Piece/Okami crossover: Where either the One Piece crew crashes into the land of Nippon and Luffy joins Ammy on her journey through it while looking for his crewmates or Ammy joins the crew from the start to where the anime currently is now. Note: If first choice, then all current crewmembers up to Thriller Bark Arc must already have joined and if second choice, must be through Post-War Arc in manga.

One Piece/NCIS crossover: Can you imagine the chaos from such a thing? Where either the One Piece crew gets sucked in to the NCIS world or the NCIS crew gets sucked into the One Piece world. If it is the latter, then let it start pre-One Piece like right after the Sabo incident.

One Piece/Star Wars crossover: This one can be quite a challenge for anyone. For instance, how would you feel if Luffy was trained in the ways of the force like a Jedi except he didn't have a lightsaber because he lost it during the Clone War, but was taught basic swordsmanship and then returns to the world of One Piece to attain his dream of becoming Pirate King? I just want someone to take a crack at this, so I can see what they decide to do with it. Oh, and see if you can use the Star Wars and One Piece content in the movie and cartoon universes. That would be really something.