My heart yearns for Ravenloft, and given that a) it was the first one licensed out in 3E, and b) it's still being supported with novels (reprints now, but with fresh novels coming next year), I think it's actually somewhat likely.
However, given the direction that both it and 4E are going, I wonder if it might not be used to jumpstart a 2nd Edition of d20 Modern (although it'd have to be more like d20 Past/Modern combined), and if it might not be better suited to that.