I'm making a game using Unity (I know, I know), and I'm implementing my own cursor because Unity doesn't let you move the system mouse cursor. Using the raw axis data, I've made a cursor that works, but it feels wrong because it doesn't have any acceleration applied to it. I'm not sure what the curve is supposed to look like, but I'd like to reproduce it. I've searched a bit and mostly only found complaints about the default acceleration curve in this or that operating system. Nobody provides an actual function.

Does anyone here know where I can find the actual calculations behind OS X' mouse acceleration?

The function is called NXGetMouseScaling, this ancient OMNI Group PDF shows how to use it. You'll have to write yourself a little bit of C, and call that from your Unity program (I understand this is possible, but know nothing about the details).

Thanks for the link. Unfortunately, I only have an Indy licence, and Unity's support for system calls is limited to the Pro version. What I might try and do is use that code to get a bunch of points from that curve and just lerp them.