>Has there been any credable research done on the consequences to the hive (not the Varroa) when "Drone Comb Varroa Control" is used?
It's not hard to figure. A frame of drone costs the bees the same resources (labor, pollen, honey, water) as a frame of workers. If they don't get drones, they will raise more. If they have enough they will spend the resources to raise workers. So every frame of drones you kill costs them a frame of workers. Is this worth it? If it's needed to control the Varroa, perhaps.