I second From Software (Demon's/Dark Souls). They know level design, interconnected 3D worlds, scary atmosphere and 3D combat with an old-school feeling - one that is faaaar away from the God of Wars or DMCs we've come to expect. And before someone says "Dark Souls is nothing like Castlevania!" (which some of you have in the past) I'd say it's not the point what you think. They wouldn't be making another Souls game. They'd be making a Castlevania with all the elements mentioned above. And it could potentially be awesome.
I also second WayForward.
Vanillaware is questionable to me though. I haven't seen anything from them that could even qualify as level design yet. That's not to say they can't do it, but I would much rather let them handle the art direction and have someone else design the actual game. They would of course have to tone down the fairy tale/story book look and go for something darker, but equally detailed.