Example code for "CopyInspector" blog post on AngryAnt.com

CopyInspector.cs

using UnityEngine;
using UnityEditor;
using System.Collections;
using System.Collections.Generic;
using System.Reflection;

public class CopyInspector : Editor
{
	static System.Type m_OriginalType;
	static Dictionary <PropertyInfo, object> m_Values;



	private List  GetProperties (Component component)
	{
		List <string> ignoredProperties;
		List  properties;

		properties = new List  ();
		ignoredProperties = new List <string> ();
		foreach (PropertyInfo propertyInfo in typeof (Component).GetProperties ())
		{
			ignoredProperties.Add (propertyInfo.Name);
		}

		foreach (PropertyInfo propertyInfo in component.GetType ().GetProperties ())
		{
			if (ignoredProperties.Contains (propertyInfo.Name))
			{
				continue;
			}
			properties.Add (propertyInfo);
		}

		return properties;
	}



	public override void OnInspectorGUI ()
	{
		DrawDefaultInspector ();
		OnCopyInspectorGUI ();
	}



	public void OnCopyInspectorGUI ()
	{
		bool enabled;
		List  properties;
		Component component;

		component = target as Component;

		if (component == null)
		{
			return;
		}

		GUILayout.Space (10.0f);

		Color backgroundColor = GUI.backgroundColor;

		GUI.backgroundColor = new Color (0.8f, 0.8f, 0.8f);

		GUILayout.BeginVertical ("Toolbar");

			GUI.backgroundColor = backgroundColor;

			GUILayout.BeginHorizontal ();

				GUILayout.Space (10.0f);

				GUILayout.Label ("Copied: " + (m_OriginalType != null ? m_OriginalType.Name : "Nothing"), "MiniLabel");

				GUILayout.FlexibleSpace ();

				if (GUILayout.Button (new GUIContent ("Copy", "Copy component values"), "MiniLabel"))
				{
					m_OriginalType = target.GetType ();

					properties = GetProperties (component);

					m_Values = new Dictionary <PropertyInfo, object> ();
					foreach (PropertyInfo property in properties)
					{
						m_Values [property] = property.GetValue (component, null);
					}
				}

				enabled = GUI.enabled;
				GUI.enabled = target.GetType () == m_OriginalType;

				GUILayout.Space (10.0f);

				if (GUILayout.Button (new GUIContent ("Paste", "Paste component values"), "MiniLabel"))
				{
					properties = GetProperties (component);
					foreach (PropertyInfo property in properties)
					{
						if (!property.CanWrite)
						{
							continue;
						}

						property.SetValue (component, m_Values [property], null);
					}
				}

				GUILayout.Space (10.0f);

				GUI.enabled = enabled;

			GUILayout.EndHorizontal ();

		GUILayout.EndVertical ();

		GUILayout.Space (-2.0f);
	}
}

CopyTransformInspector.cs

using UnityEngine;
using UnityEditor;
using System.Collections;


[CustomEditor (typeof (Transform))]
public class CopyTransformInspector : CopyInspector
{
	public override void OnInspectorGUI ()
	{
		Transform transform;
		Vector3 localPosition, localScale;
		Quaternion localRotation;

		transform = target as Transform;

		localPosition = EditorGUILayout.Vector3Field ("Position", transform.localPosition);
		localRotation = Quaternion.Euler (EditorGUILayout.Vector3Field ("Rotation", transform.localRotation.eulerAngles));
		localScale = EditorGUILayout.Vector3Field ("Scale", transform.localScale);

		if (GUI.changed)
		{
			transform.localPosition = localPosition;
			transform.localRotation = localRotation;
			transform.localScale = localScale;
		}

		OnCopyInspectorGUI ();
	}
}

CopyYourComponentTypeInspector.cs

using UnityEngine;
using UnityEditor;
using System.Collections;

[CustomEditor (typeof (YourComponentType))]
public class CopyYourComponentTypeInspector : CopyInspector{}

Hello.
I've forked this code => https://gist.github.com/mushutehk/6636510
and modified it so that it works 100%
it can also now handle the copying of multiple components (though currently only the Transform component is implemented).

@AngryAnt Thanks for sharing the original code. I'm new and hence don't yet know the general conduct of Git so if it's not considered "nice" to go around forking everyones code, let me know and I can take it down.

Otherwise I hope people can find this as useful as I have.