A ball and spring - multiple degrees of freedom

I'm trying to create a ball and spring effect, where a ball attached to a spring pops out of a box. I've figured out this in one dimension using the spring joint, and this snippet for "adjusting" the size of the spring" (fudging a bit, the extra length is "below the floor"):

var ballT:Transform;
function Update () {
    transform.localScale.y = 
          Mathf.Abs(ballT.position.y) - 
           (ballT.localScale.y*ballT.lossyScale.y/2)/transform.lossyScale.y;
}

I'm wondering how would I create a spring with more than one degree of freedom?

1) Some sort of mesh along spline manipulation for the spring?

2) How would the spring joint work for multiple dimensions - where the spring is soft enough to "bend over" and skew?