Step 1: Equip a sword in your first slot, and a gun in your second slot.
Step 2: switch weapons (Click on the weapon in slot one, and switch it to slot 2)
Step 3: You will be holding your gun like a sword! (Or the other way around)
NOTE: this only works in the character screen
Examples:
http://i.imgur.com/0UkRM.jpg
http://i.imgur.com/FCbvl.jpg
http://i.imgur.com/gIYnK.jpg
Also made my knight have no weapon somehow... http://i.imgur.com/1gzWm.jpg
Here is a video showing how to do it: http://www.youtube.com/watch?v=LIxfiOjAbh4&feature=youtu.be
Even when you hold the sword like a gun, or the gun like a sword, it looks pretty natural. I think the swords look more menacing when you hold it up, at your side. Maybe we can change how we hold the weapon in the future?