SmartCreate.cs

using UnityEngine;
using UnityEditor;
/**
 * originally by buffonomics
 * originally posted on: http://forum.unity3d.com/threads/77444-How-to-create-new-GameObject-as-child-in-hierarchy 
 */

public class SmartCreate : MonoBehaviour {
    [MenuItem("GameObject/Create Empty Parent #&e")]
    static void createEmptyParent() {
        GameObject go = new GameObject("GameObject");
        if (Selection.activeTransform != null) {
            go.transform.parent = Selection.activeTransform.parent;
            go.transform.Translate(Selection.activeTransform.position);
            go.transform.localPosition = new Vector3(0, 0, 0);
            go.transform.localScale = new Vector3(1, 1, 1);
            go.transform.localRotation = new Quaternion(0, 0, 0, 1);
            Selection.activeTransform.parent = go.transform;
        }
    }


    [MenuItem("GameObject/Create Empty Duplicate #&d")]
    static void createEmptyDuplicate() {
        GameObject go = new GameObject("GameObject");
        if (Selection.activeTransform != null) {
            go.transform.parent = Selection.activeTransform.parent;
            go.transform.Translate(Selection.activeTransform.position);
        }
    }



    [MenuItem("GameObject/Create Empty Child #&c")]
    static void createEmptyChild() {
        GameObject go = new GameObject("GameObject");
        if (Selection.activeTransform != null) {

            go.transform.parent = Selection.activeTransform;
            go.transform.Translate(Selection.activeTransform.position);
            go.transform.localPosition = new Vector3(0, 0, 0);
            go.transform.localScale = new Vector3(1, 1, 1);
            go.transform.localRotation = new Quaternion(0, 0, 0, 1);
        }
    }

}