Crossover of Rurouni Kenshin and Fullmetal Alchemist! This is for a story I'd like to start writing.... well.. I started a small outline of it so far...

Summary:

Edward and Alphonse Elric came from Germany to Japan as young boys to stay with their mother. After their mother dies, the two brothers train with a swords-master, and soon join the Bakumatsu war as hitokiri, as does Kenshin Himura. The elder brother, Edward, often took the role of hitokiri to protect his younger brother from harm, but after losing two of his limbs in battle, his younger brother Al takes over as the next hitokiri.

Years later, as Kenshin is living peacefully in Tokyo, he hears rumors of two nearly identical samurai wielding swords illegally through town...