The Rocket Slime spin-off was an enjoyable Nintendo DS outing. Its 3DS sequel aims to be the same, but for the 3DS.
The second entry in the Dragon Quest Heroes was localized as Dragon Quest Heroes: Rocket Slime back in 2006 when it was released in North America.
The third entry, which I guess could be localized as Dragon Quest Heroes: Rocket Slime 2 is slated for the Nintendo 3DS on November 2. A direct translation of the game's title is Slime Mori Mori Dragon Quest 3: The Great Pirate Ship and the Tails Brigade.
The game promises epic sea battles and epic shooting-Slimes-out-of-cannons.