Gauntlet DS has been removed or changed to a nebulous status on several retail sites. GoNintendo took notice that the title was removed from GameStop; allegedly, Amazon told customers that the game had been "canceled." Furthermore, Eidos no longer makes any mention of the title on its site.
A source familiar with the development of the title has confirmed to Joystiq that Gauntlet DS has indeed been scrapped; however, we've contacted both Eidos and developer Backbone Entertainment to learn what has (or hasn't) befallen the DS dungeon crawler. We'll update as soon as we hear something official.