Wild Cherry Blossom
It's the best Naruto/Ranma cross I've ever seen, and I hope that future Ranma/Naruto crosses on our side take this as the bar to aim for. Plot, system, and character points are all solid. It has a nekoken-based cross premise that doesn't suck, and a personality melding exploration that's well thought out. Anyways, read the thing and see for yourselves.