This dev diary for Zombie Studios' downloadable shooter BlackLight: Tango Down sheds some light on how six core weapon systems can be modified into "literally trillions of different weapon combinations."
That's what the official release that came along with the video said at least. It's a lofty claim, but one that can be easily validated using advanced maths techniques I'm not familiar with. What I do know is that six core weapon systems plus twenty-five different weapon attributes plus a host of adorable, perk-granting weapon charms equals a whole lot of variety.
Not only that, but as Zombie points out in the video , you can really make a weapon your own, to the point where 'Kill Fahey, take his gun,' could become a common first order of business in multiplayer matches.
I can dream.