こんなんで1フレームずつ進むかな

var animName : String = "";
var frame : int = 0;

function Start () {
animation.Play(animName);
animation[animName].speed = 0;
}

function Update () {
++frame;
var state : AnimationState = animation[animName];
var maxFrame : int = Mathf.FloorToInt(state.length * 60);
frame = Mathf.Repeat(frame, maxFrame);
state.time = frame / 60.0f;
}