I'm not really sure how useful this would be, or the criteria you'd need to fulfill to get this. I though that it would be fun, nonetheless.
Basically a perk that allows you to use a 2 or 3 AP melee attack with a gun equipped. possibly only available with a certain level of one of the guns skills and high melee weapon percentage. It should probably have a chance to damage your weapon and the effectiveness of the attack should partially be based on the strength required to operate the weapon.
What do you think?