A Dolly Zoom(or vertigo effect) in real life actually uses the focal length(focal length = zoom), so animating the focal length is the only way to achieve the change in lens compression that gives the effect. https://www.youtube.com/watch?v=VYNbcT8tN40
Really an Awesome idea and rig to provide for us....a camera, its so important!
Great job!!!
I didn't think a dollyzoom was possible in 3D because the zoomfunction isn't a real zoom. Seems like you managed to animate the focallenght of the lens. Cooolll... :)