Back before the site overhaul, the gallery section had a wallpaper section in it from Nintendo's old site. I can't currently find any of these wallpapers.
The wallpapers I remember seeing consisted of the following images made from TCG art:
* Bord, Cord and Barst standing together.
* The three Whitewings standing together.
They weren't exactly the most dramatic/unique wallpapers, but it'd be nice to have them reposted again.
EDIT: Another Fire Emblem site still has the wallpapers.