The means of introducing wheelbrakes seem to already be availible. While my friend was tweaking config files for the civilian SUV, he was able to increase the torque to the point where, if the handbrake was held and the accelerator floored, the front wheels would spin, allowing the car to accelerate extremely rapidly upon the release of the handbrake.
This shows that it is indeed possible to have brakes function independently of acceleration, and it needs only to be implemented by BI.