Signature Arms and Armors

A new idea for use by the Player Characters has come to my mind.  This is the idea of allowing them to have a signature item that is developed by their most often used armor and weapon.  They are able to pay a skilled Non Player Character to combine these 2 pieces into a single piece that will do both defensive and offensive effects.  This new item gain a +1 bonus based on their technological era( +1 for Futuristic, +2 for Modern, and +3 for historic) and a game master specified special ability based on how the character has been designed.  This can be done at level 5 for a single item.