Square Enix has recently trademarked Chapters of the Chosen. It is probably not too much longer before we get a USA release date on Dragon Quest IV DS Chapters of the Chosen. Likely it will be a significant time after July 22nd when Final Fantasy IV DS comes (think fall or winter for Dragon Quest IV DS Chapters of the Chosen).
Over in Japan (like usual) Dragon Quest IV DS sold a ton of copies and got great reviews. They love the series there and it there is still a niche in the USA especially after a more mainstream success with Dragon Quest VIII.
There are 5 chapters in Chapters of the Chosen Dragon Quest IV with Ragnar’s, Alena’s, Taloon’s, Mara’s / Nara’s and the main character in Chapter 5, where everything comes together.
Actually though, there is a secret sixth chapter only in Dragon Quest IV DS. You can get Psaro the Manslayer in your party! And then fight some tough monsters that oppose Psaro like Aamon.