Conquest of the Horde

Just wondering if there is a Marksman/sniper/really long range attacker prestige class?

There is.

Prestige Classes

There are numerous ranged prestige classes, such as:
Dark Ranger
Dead Shot
Elven Ranger
Gunman
And even Marksman, which apparently, doesn't have a page yet.

It's all in our wiki, as the first link indicates.

Going to all that effort Skaar?

That'd be my problem.