I've been holding on to these wallpapers for a while because I wasn't sure if Atlus USA was planning on making them available. Now that it looks like that won't be happening, I feel OK about sticking them up on the site. These were only available on the Japanese bonus disc that came with pre-ordering the game. They were kindly provided to me months ago by a member of NeoGAF, although unfortunately I'm not sure who it was any longer (feel free to let me know if you know).
Here's a preview:
http://www.digitaldevildb.com/images/wallpapers/persona3/bonusdisc/blue_tmb.jpg" alt="Persona 3 Wallpaper" height="113" width="150" />
http://www.digitaldevildb.com/images/wallpapers/persona3/bonusdisc/school_tmb.jpg" alt="Persona 3 Wallpaper" height="113" width="150" />
http://www.digitaldevildb.com/images/wallpapers/persona3/bonusdisc/sees_tmb.jpg" alt="Persona 3 Wallpaper" height="113" width="150" />
http://www.digitaldevildb.com/images/wallpapers/persona3/bonusdisc/hero_tmb.jpg" alt="Persona 3 Wallpaper" height="113" width="150" />
http://www.digitaldevildb.com/images/wallpapers/persona3/bonusdisc/aigispaint_tmb.jpg" alt="Persona 3 Wallpaper" height="113" width="150" />
http://www.digitaldevildb.com/images/wallpapers/persona3/bonusdisc/shadowtime_tmb.jpg" alt="Persona 3 Wallpaper" height="113" width="150" />
http://www.digitaldevildb.com/images/wallpapers/persona3/bonusdisc/dogpersona_tmb.jpg" alt="Persona 3 Wallpaper" height="113" width="150" />
http://www.digitaldevildb.com/images/wallpapers/persona3/bonusdisc/aigispersona_tmb.jpg" alt="Persona 3 Wallpaper" height="113" width="150" />
http://www.digitaldevildb.com/images/wallpapers/persona3/bonusdisc/heropersona_tmb.jpg" alt="Persona 3 Wallpaper" height="113" width="150" />
http://www.digitaldevildb.com/images/wallpapers/persona3/bonusdisc/yukaripersona_tmb.jpg" alt="Persona 3 Wallpaper" height="113" width="150" />
Anyway, you can check them out (along with the older selection) in our
http://www.digitaldevildb.com/games/persona3/wallpapers.php">
Persona 3 wallpapers section. They're all available in 800x600, 1024x768 and 1280x1024.