7 Deadly Sins

I've been tossing around story ideas in my mind, and haven't really been getting to them. For example, if we have the Elements of Harmony, why don't we have the 7 Deadly Sins? It only came to mind after watching animes featuring it, namely Fullmetal Alchemist and Trinity 7. I might get to this eventually, but the biggest issue is coming up with characters. If you like the idea, I'd like to see you give it a shot, or you can leave a link in a comment to a story that features this theme.