I Have an Idea

I had an idea a week ago that's been floating around in my head ever since, and I want to try writing it. It HAS been done before, but, I wanna write it, so who cares.

Imagine a darker, grittier alternate MLP universe where life is like prohibition America. Cars, guns, and drugs exist in this universe, ponies can die by the hoof of the mafia. Octavia is the daughter of the godfather of the mafia, and his right-hoof mare. The mane six take various roles, along with a few other characters, and Octavia's gal, Vinyl Scratch.

I have the basic character outlines written out, but I want to see if anyone has any opinions. It would be a dark, gritty story, and I can't guarantee everypony makes it through the story alive.