AH! Just figured it out. Anyone who wants a quick fix, feel free to copy this code... Open up the mouselook script and change this...

    float rotationY = 0F;

void Update ()
{
    if (axes == RotationAxes.MouseXAndY)
    {
        float rotationX = transform.localEulerAngles.y + Input.GetAxis("Mouse X") * sensitivityX;

        rotationY += Input.GetAxis("Mouse Y") * sensitivityY;
        rotationY = Mathf.Clamp (rotationY, minimumY, maximumY);

        transform.localEulerAngles = new Vector3(-rotationY, rotationX, 0);
    }

To this...

    float rotationX = 0F;
float rotationY = 0F;

void Update ()
{
    if (axes == RotationAxes.MouseXAndY)
    {
        rotationX += Input.GetAxis("Mouse X") * sensitivityX;
        rotationX = Mathf.Clamp (rotationX, minimumX, maximumX);

        rotationY += Input.GetAxis("Mouse Y") * sensitivityY;
        rotationY = Mathf.Clamp (rotationY, minimumY, maximumY);

        transform.localEulerAngles = new Vector3(-rotationY, rotationX, 0);
    }

I think it's a little ridiculous how they scripted this script by using variables that are never put into use. Hopefully one of the developers will get a glance of this and fix it in the next release :)

It seems important to allow the camera to do full rotations on X axis if needed. Something like that will allow it ( if minimumX equals maximumX ):

 if (axes == RotationAxes.MouseXAndY) {
    if (minimumX == maximumX) {
       rotationX = transform.localEulerAngles.y + Input.GetAxis("Mouse X") * sensitivityX;
    }
    else {
       rotationX += Input.GetAxis("Mouse X") * sensitivityX;
       rotationX = Mathf.Clamp(rotationX, minimumX, maximumX);          
    }
    rotationY += Input.GetAxis("Mouse Y") * sensitivityY;
    rotationY = Mathf.Clamp (rotationY, minimumY, maximumY);
    transform.localEulerAngles = new Vector3(-rotationY, rotationX, 0);
}

That worked a treat "alexmon27", thanks.