As it turns out, the impressive golden sword that won second place is actually copied from Deviant Art user Wen-M, who uploaded the original version in 2004. "LOL, thanks," Wen-M said when a fan congratulated him on his entry. "Unfortunately I did not enter, someone lacking honesty used my work without permission. some friends informed me about it. XD ah...people."
You can read more on the other contest entries on the official forum thread.
[Thanks to all who sent this in!]
Update: Trion has responded with an explanation of its investigation of the accusations. In an email to Massively, the studio wrote, "Thanks to our users we were able to verify that this image was indeed appropriated from another artist. We of course disqualified the entry, and did a more thorough search to make sure that no other entries were also inappropriately submitted. We've reached out to the artist (who does absolutely amazing work, and is definitely worth checking out) both publicly and privately apologizing for this use of his art. We've adjusted the list of winners (viewable here), and congratulate all of the incredibly talented folks who participated in this contest." Congratulations to all of the legitimate winners!