I would suggest a dwarven blacksmith ability.

You could use it on weapons of workable metals. The difficulty of success would be dependant on the hardness of the matal, in the same ways weaponbreaker is affected by them. Enhanced weapons could gain a small boost to average and hit/dam roll(or one of them), dependant on skill level and character level. If you fail the skill there is a chance to destroy the weapon, also dependant on the strenght of metal, and inherent power of weapon(how limited, what level). Mithril/iron would be much harder to destroy or enhance than steel of course.

This could only be done in blacksmith rooms with a forge. Like in mortorn, and various places around the world.