In the campaign I run, we've had one Rogue (thief) who just liked the gunsmith gimmick so he could fight with a shortsword-bayonetted carbine, and have a pair of pistols in a pinch. The player had to leave after the 1st adventure.
And we have a player considering bringing in a Ranger (scout) who uses paired pistol-handaxes if his current ridiculously overpowered pixie hexblade dies.
But the party already has a gunsmith, Rosetta, a . . . hehe, God, I love 4th edition . . . a Deva seeker/psion who uses a silenced musket. Her powers are all flavored as using telekinesis to curve bullets, or to plant a bullet in a target, then grab the bullet and yank the person around from inside.
Basically, she's every conspiracy theorists' dream. She fires just about every kind of magic bullet you could want.
Oh, and it's a lesser cloaked musket, so in a pinch she can turn it invisible and walk through a crowd.