a European trademark filed by Konami for something called "Harmony of Despair," and they correctly point out that it certainly sounds like another Castlevania game. Since the classic Symphony of the Night, Castlevania games are often subtitled with music-themed "X of X" titles, including Lament of Innocence and Aria of Sorrow, and the upcoming Castlevania: Lords of Shadow.
There's no indication in the trademark exactly what the game will be (it's just marked as "video game software" and related services), and while Dawn of Sorrow, the series' first DS title, gave an acronymic hint to the system, obviously Harmony of Despair doesn't. Wait -- "H.D."? It must be for the rumored iPhone HD releasing later this year! Mystery solved!