Hm... I would most likely make a gun similar to the Yazuka's Walther P-38, the only thing I would change about it is the size, I would enhance the size a touch in order to increase the power and lethality of it. I would also make the handle with an out gel coating, that way it feels nice. It's all about the feel. ^^
A laser super light-weight rifle that could be folded into the size of a penny when not in use. In penny form it can be thrown as a smoke bomb and is reusable