Game Engine: mouse acceleration

[CrystalViolet]

Simple idea, but one that can make or break the controls in a game (I'm looking at you Bioshock). I'd like to see the devs make ingame mouse acceleration toggleable and adjustable for each control scheme.

Example settings might be:

On foot = off
Ground vehicles = 30%
Aircraft = 60%

This would go a long way towards making the controls responsive and usable.