Sonic Chronicles: The Dark Brotherhood for the Nintendo DS was BioWare's first Nintendo DS game, and the first RPG based around the Sonic the Hedgehog series. It was released on September 30, 2008, and was generally well received.
Episode 6 of SavyGamer.co.uk's podcast included an interview with Sonic Chronicles' associate producer, Dorian Keiken, where he spoke about BioWare's future in regards to the Nintendo DS. During this interview (which begins approximately 35:26 into the podcast), Dorian states that the story for a second Sonic Chronicles game is already being written. While this is not necessarily official confirmation that a second Sonic Chronicles game will be released, it is at least a sign that the inclination exists within BioWare to do so (and some may say the ending of the first game shows this as well). Look for RPGamer to have the official announcement of a second Sonic Chronicles game if it is made.