I have an idea: Wristblades. They can be used with any weapon (or alone), maybe if we implement melee with all weapons, they will add an extra animation and more power, but they are powerup style and have to be found first. I think it would be cool if, while firing the RL at a distant target, you could go one-handed and keep firing, while whipping your other arm out to slash to the side as you were running by some hapless victim... Double Kill!
Ever watched Angel? There's this cool weapon that straps to the inside of the arm, and when you flick your arm out this blade extends from it and you grab it with your hand to fight, Looks deadly cool Perhaos as an option for a customiseable sword, since someone brought up custom models.
Yeah, in fact, with all the cool TV and movie inspired custom characters running around out there, a wide variety of melee weapons would be the perfect way to support them. All we have to do is take some examples from popular sci-fi/fantasy media and see if we can implement them. I think people would love that. Then there's the mix-and-match possibilities...
Imagine: Homer Simpson with Wolverine's blades... heh
How about some giant boltcutters - like a pair of industrial strength scissors? With the varying stances mentioned earlier, maybe you would stab with them in the weak stance, swing them in the medium stance and chop a bot in half with the maximum setting?