Custom mouse acceleration per axis?

[Blastfrog]

Is there some kind of way to make Windows use a different acceleration curve on either axis, as opposed to both axes sharing the same curve?

 

This is gonna sound really weird, but I want to have negative acceleration horizontally, but positive acceleration vertically. After some experimentation, I've found that such settings actually improve my aim significantly, but the problem is that as of right now, I have to choose one or the other for both axes.

[Nevander]

I actually hate when games do this. I feel like GZDoom actually does it, the up and down seems slower than left and right. Makes aiming up and down awkward sometimes.