Maaan, Borderlands has inspired me to construct a full automated dungeon crawl system with random loot for Dark Heresy. My rough draft right now is the players roll X d100, to determine Brand, Weapon-Class (Pistol, Basic, Heavy), Type (SP, Bolt, Las, etc), RoF, Damage, Reload Speed, Range, Weapon Upgrades, Special Quality (and number of), and probably others as well. The brands will probably give you one special quality and one feature unique to the brand.
Here's a few on the top of my head;
Maliwan: Roll 1d3, gain Shock, Flame or Toxic. On a 10 on damage, roll 1d5 on critical hits table.
Dahl: Can Semi-Auto as a half-action.
Hyperion: Gain Accurate. If weapon already has accurate, aim as a free action instead. If flame, shoots a 20-30m line instead.
Jakobs: Tearing. If weapon already has tearing, add 1d10 to damage instead. All Melta, Plasma and Las weapons become SP or Bolt instead.
Torque: Damage type becomes explosive. On a 9 or 10 on damage, roll 1d10 on critical hits table.
Vladof. Double RoF, single shot included. If there is no full auto, gain full auto equal to twice the weapon's semi auto.
Will probably report this on appropriate board after I made a complete chart on excel.