Some of the Artifact Weapon Models
These images were taken from the Blizzcon WoW Game Systems Panel and uploaded to MMO. I figured out which class each belonged to and here they are:
Frost DK:
Unholy DK:
Havoc DH/Marksman Hunter:
Balance Druid:
Resto Druid:
Beastmaster Hunter/Fury Warrior:
Survival Hunter:
Arcane Mage:
Fire Mage:
Frost Mage:
Brewmaster Monk:
Mistweaver Monk:
Windwalker Monk:
Holy Paladin:
Prot Paladin:
Discipline Priest:
Holy Priest:
Shadow Priest:
Assassination Rogue:
Outlaw Rogue:
Subtlety Rogue:
Elemental Shaman:
Resto Shaman:
Destruction Warlock:
Prot Warrior:
Retribution Paladin:
Enhancement Shaman:
Affliction Warlock:
Also MMO forgot this one so I screencapped it for you. It's Blood DK:
Also Blizzard didn't show all the variants for all the weapons. Seems they left out Vengeance DH, Demo Lock, Feral Kitty and Bear so here is the link to the artifact site:
http://us.battle.net/wow/en/game/artifacts/You don't see as many variants there, but you can see a few variants for the specs they left out of the panel.