A DS with decals of Final Fantasy is rumored to hit da streets later this year. Maybe it will have spiecial features with da game.
There were a couple limited edition Final Fantasy DS's released in Japan.
http://pgrevolution.com/wp-content/uploads/2006/09/ff-ds-lite.jpg
http://www.plasticbamboo.com/wp/wp/wp-content/uploads/final_fantasy_ds_lite.jpg
The FF III one looks nice.