OK, this is gonna be quick, since I don't want to forget about it, but another ability I thought about:

Sitting Duck (Ex): At 3rd level an archer may spend a full-attack action to focus on his target, excluding everything else from thought. He fires a single ranged attack that ignores Wind Wall and he gets a -2 penalty to AC. At 6th level he may ignore miss chances from concealment and spells like blur. At 11th level he may make a second shot and his AC penalty is reduced by 1. At 16th level he may fire through effects like Wall of Force or Force Cage and the attacks are ranged touch attacks. At 20th level he may fire a third arrow, and he no longer receives a penalty to AC.

Okay, it's very rough at the moment, and I'm quite sure i don't know all the different effects that affect ranged weapons. I'm also sure that when he gets the various abilities could stand to be tweaked. Like I said, I just wanted it up before I forgot about it. What do you think?