Simple editor script to duplicate animation clips found in the selected model/animation asset file. Duplicates unlike original animation clips may be edited.

Editor_DuplicateAnimationAsset

// NoiseCrime Gist
// 2014.07.16
// Unity Version: 3.5.7+

// Simple editor script to duplicate animation clips found in the selected model/animation asset file.
// Duplicates unlike original animation clips may be edited.

using UnityEngine;
using UnityEditor;

public class Editor_DuplicateAnimationAsset : EditorWindow 
{
	[MenuItem("Assets/Duplicate Animation Assets (NoiseCrime)")]
	static void DoCreateAnimationAssets() 
	{
		if (Selection.activeGameObject.GetComponent<Animation>() != null) 
		{
			// Validate Folder Exists
			if( !System.IO.Directory.Exists(Application.dataPath + "/DuplicatedAnimationClips"))
			{
				AssetDatabase.CreateFolder("Assets", "DuplicatedAnimationClips");
			}

			Animation anim = Selection.activeGameObject.GetComponent<Animation>();
			
			foreach (AnimationState sourceClip in anim) 
			{

#if UNITY_4_3
				AnimationClip newClip = new AnimationClip();
				EditorUtility.CopySerialized(sourceClip.clip, newClip);
				AssetDatabase.CreateAsset(newClip, string.Format("Assets/DuplicatedAnimationClips/{0}_dup.anim", sourceClip.name));
#else
				// Unity 3.5.7
				AssetDatabase.CreateAsset(sourceClip.clip, string.Format("Assets/DuplicatedAnimationClips/{0}_dup.anim", sourceClip.name));
#endif
			}
		}
	}
}