Maximum speed mouse follow without rotation

Hi, I'm just starting out and I'm trying to get a character to follow the mouse which I've seen a lot of help for. My problem is that I need the character not to rotate toward the mouse, they need to just move to it. I also want to cap the speed that they can follow the mouse. Smooth follow was the closest I came so far, but it slows me down too much as I approach the mouse.

So to recap my main goals are:

• Follow the mouse
• Don't rotate
• Move at a constant speed
• Don't go faster than a maximum speed

Here's the closest I have so far... most of this was put together from other answers on this site:

var target : Transform; var smoothTime = 0.3;

 var playerPlane = new Plane(Vector3.up, transform.position);
 var ray = Camera.main.ScreenPointToRay (Input.mousePosition);
 var hitdist = 0.0;

 if (playerPlane.Raycast (ray, hitdist)) {

     var targetPoint = ray.GetPoint(hitdist);
 }

 thisTransform.position.x = Mathf.Lerp( thisTransform.position.x, targetPoint.x, Time.deltaTime * smoothTime);
 Debug.Log(thisTransform.position.x);
 thisTransform.position.z = Mathf.Lerp( thisTransform.position.z, targetPoint.z, Time.deltaTime * smoothTime);
 Debug.Log(thisTransform.position.z);

}