Draw a Cone. Pass this into handle functions.

Note: Use HandleUtility.GetHandleSize where you might want to have constant screen-sized handles.

Cone Cap in the Scene View.

	// Draw one cone on each axis that points where the transform is looking at
	//
	// Usage: Attach the "DummyCubeCapScript.js" script to any Object you want
	// See this working on
	
	@CustomEditor (DummyConeCapScript)
	class ConeCap extends Editor {
		
		var coneSize : float = 1;
	
	    function OnSceneGUI () {
	    	Handles.color = Color.red;
	    	Handles.ConeCap(0,
				target.transform.position + Vector3(-5,0,0),
				target.transform.rotation,
				coneSize);
	    	Handles.color = Color.green;
	    	Handles.ConeCap(0,
				target.transform.position + Vector3(0,-5,0),
				target.transform.rotation,
				coneSize);    	
	    	Handles.color = Color.blue;
	    	Handles.ConeCap(0,
				target.transform.position + Vector3(0,0,-5),
				target.transform.rotation,
				coneSize);
	    }
	}

And the script attached to this Handle:

	//DummyCubeCapScript.js
	
	Debug.Log("I have CubeCap Handles attached to this transform!");