I was able to achieve the effect I wanted by using a hinge joint and increasing the motor force and target velocity.

I would try experimenting with the physics properties more. Change the mass of the flippers and the ball if you haven't already, and physic materials sound very helpful here. Add a bouncy physic material if you haven't already, and the ball will bounce without much coding, and Unity would handle all the forces for you.

Then, if you need to, you could add force when the ball collides with the flipper Rigidbody.AddForce(Direction : Vector3).

One function...

 function FixedUpdate () {
    rigidbody.AddForce (Vector3.up * 10);
}

-Hope I helped, Gibson