This is what I call the "benevolent sniper" build and I need some help with it.
The idea is that the character travels seperately from the rest of the party. Usually, as a kind of backup or getting a clear shot in for example a flying enemy or picking off routing enemies.
However, what is supposed to make this build special is the distance at which the character can not only attack, but also aid his team-mates. With a telescope and some kind of large range magic or contraption, he delivers buffs, healing and special effects from a safe, safe distance, usually with limited ammunition.
Think Gandalf who arrives in the nick of time to save the company from three trolls by breaking a rock that blocks the valley from the sunlight that will turn them to stone. "A wizard is never late, Bilbo Baggins. He arrives exactly when he means to". That sort of stuff, except with the party being aware of the wizard's location when they need him.
The way I was thinking of doing this at first was as an alchemist with the "explosive missile" discovery so I can apply the effects of bombs to one of my weapons. However, the feat tax required to make such a narrow concept work probably make that build non-viable.
Perhaps someone else can recommend a build? Something like Spellslinger or Holy Gun? Or something to that effect through cleric abilities? I don't know if I remember a cleric whom can deliver his spells through his weapons, though it does sound something obscure that a cleric or similar class could have.
Hmm... I could take Oracle with the Metal Mystery.
It adds flavour, but there's actually a good use for it too; if you take Dance of the Blades, you can move faster and at level 7, gain additional attack points with your weapon, because guns are made mostly out of metal. You can also get "Vision in Iron", allowing you to use any piece of polished metal at least the size of a dagger as a scrying device, as if using the spell scrying. Which is basically saying that my gun has a scope on it, except I can see where enemies are. How awesome is that?
If I take Oracle and Wizard, I could go into Mystic Theurge too. That way, I increase the "ammunition" that I have available to me and I become more flexible in the long run. With Enlightend Philosopher, I can raise my intelligence by at least one, perhaps two points, making the saves for my Wizard more effective.
I'm looking into other healing classes too; druid, shaman, inquisitor, warpriest and cleric. More on that when I got more on that.