Well, they were implemented and found ingame.
Isn't that what you were asking, sorry if i'm misunderstanding :P.
Oh and this is what the winners got.
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More prizes! More recognition!
Because the quality of the entries was so high, we've decided to change the prize schedule to recognize even more Guild Wars fans, and to give them the credit—and the loot!—that they so richly deserve. Here is the new prize list:
Winners: Each of the eleven winners will receive their choice of a copy of Guild Wars Nightfall (standard edition) signed by the Guild Wars Development Team or a full set of Guild Wars Skill Pin Set #1 or a PvP Unlock Pack. In addition, each winner will receive a Guild Wars Nightfall t-shirt and a code for a Guild Wars character slot, if character slots are available in their location.
Honorable Mentions: Each of the seventeen honorable mention recipients will receive A Guild Wars Nightfall t-shirt and a Guild Wars character slot and Two (2) random Guild Wars Skill Pins
Finalists: Each of the seventy-nine Finalists will receive two random Guild Wars Skill Pins.
All of the weapons are not in the game yet. ArenaNet said more later.
From their website
"Design-a-Weapon Items: The Hunt is On! 5 March 2008
We are pleased to announce that we will add a few of the winning items from the most recent Design-a-Weapon Contest into the game later this week. Your assignment, should you choose to accept it, is to venture forth and find those items. We'll add another group of items in the future, so keep your eye on this page for more information in the coming weeks."