The most recent issue of Nintendo Power dropped some not-so-subtle hints as to the feature game for their next issue:

We can't tell you what's on the next issue's cover but trust us-we've go the biggest scoop of the year so far! As mysterious as a new moon, the follow-up to one of 2005's best DS titles is a whip-smart adventure that you won't want to miss.

New moon? Whip-smart adventure? It must be.. A new Yoshi's Cookie!

Oh, wait, or a new Castlevania. They're moving fast, as Castlevania: Dawn of Sorrow was released on the DS just six months ago.

Source: 1up