The only thing I'm aware of is related to the parallax user studies for interactive touch screens, try searching for "User Model for Predictive Calibration Control on Interactive Screens" but this is user studies related to mechanical touch screen studies. You might have better luck looking for 'Parallax Error' and 'User Viewpoint' if your goal is to disprove that it coincides with user-centered practices.
I'd personally say that the best thing is to create your own study and publish your findings. I think the parallax effect can add to the user interface's 3D depth, thus increase emotional response to using the interface: I think it can be good thing, depending on the audiences' bias, as long as it is keyboard accessible.
Of possible interest related to the topic: http://3.7designs.co/blog/2012/01/parallax-scrolling-effect-12-tutorials-an/