So, I'm interested in running a mafia game, and I have two concepts that I'd be okay with.

1. (And this is my preference)
 This would involve a large number of players vying for position among the criminal hierarchy. There would be a limited pool of resources, which you would fight, scheme, and betray for. Player deaths can and will happen, but the ultimate goal is to achieve the position of boss, and head your own family.

2.
Alternatively, I'd be willing to run a story oriented campaign centered around two or three main characters trying to survive in the underworld, or achieve... well, whatever you please. Again, player deaths will happen, so be wary.

Would anyone be interested in playing, and are there any systems that would be ideal? I'm not opposed to free-form either.

What years would you set it in?  What type of mafia are you interested in?  If you were going to use a system, which do you prefer for it?

I imagine Prohibition-era, or even earlier. I'm open to systems; however I do enjoy the storytelling aspect of free-form. Is there a particular system you feel would either of these scenarios?

I tried a prohibition-era game with FATE before. I thought it would be good, because working to uncover your rivals' Aspects would make a good mechanic. Didn't really get off the ground, so I can't say one way or the other.

Depends if we're looking for a high-action pulp-style adventure, or a more thoughtful, character-driven narrative.

Fate would save us from the risk of godmoding, which is a good thing. That would give it an interesting twist, since you could never be entirely certain, you will succeed with the task you are attempting, which would provide some interesting narrative.