The latest rumour suggests that Konami will be announcing a new Castlevainia game called Castlevainia: Mirror of Fate at E3.
This comes via the Dutch website N1tendo who deduced from Konami's E3 schedule that the new game will be announced. According to N1tendo, the game will be called Mirror of Fate and will have two members of theLords of Shadow creative team on board: producer David Cox and writer/director Enric Alvarez.
This is all unconfirmed, but the broad strokes of it sound good, at least. I loved Order of Ecclesia on DS, so I'll gladly play another handheld Castlevainia game.