I am trying to decide between running a political type game with some combat (similar to Dark Ages: Vampire), or a Fall Out style campaign (maybe even Shadowrun).
I've seen builds and ideas on here with people using Pathfinder as the base system for things like this. However, I am looking at if I should limit certain classes, or even go so far as allowing the alternate alignments (unearthed arcana) for Paladins to allow for more gritty feel.
Has anyone done any of this and can lend ideas or tidbits?
Honestly, I think that provided you have a willing group of players, you can make the rules work for most anything. I say most because I think if you start to get into technology that's too advanced (machine guns, lasers, tanks, etc.) you might as well just go with a system designed for it (like Shadowrun). That said though, there's no reason you can't run something that's fairly steampunky with the pathfinder rule set. It just depends on how much technology you are looking to incorporate. A good example campaign might be the Zeitgeist campaign by ENWorld (which they even have available for pathfinder).
As far as alignments go, personally I have no problem with dropping alignments from the game. By and large it won't change things all that much. About the only thing that really comes to mind are things like Protection from Evil/Good/Chaos, etc. and the multiclassing restrictions you often find with alignments (Monk/Barbs are rare, etc.)