In a perfect world, the "Alucardvania" would be retrofitted to the PS Vita. However there's no indication that this will happen (yet).
David's Cox confirmed that there were other CV projects that were being pitched to Konami, but those were canned in favour of his LoS. Also, when asked if he had any info on the "Alucardvania," he promptly replied, "I have no idea."
Also, a motion-capture actor did an interview several months back confirming that he went to Japan to do work on a 3D Castlevania game, then later said that the project was canceled for reasons he didn't know. I'd provide the link but I didn't save it, it's on this forum a few pages back somewhere though.
The only way we'll get a straight answer is if IGA ever does another interview again. Last time he did one was in 2008.