I am planning on building several hives this winter with straight sides (tanzanian), and the length of two supers long. They should fit 21 frames on the bottom hive body, so I can fit 2 supers on top -back to back. I want to make it so I can interchange frames from a standard hive. I have heard many people mention this idea, and even seen a hive like it on the Bush site. Has anyone experienced any downside to this method.