You are correct, you do not need the drawer in the 49" corner cabinet. Sometimes I think is is just easier for IKEA to show it with the drawer, because it is a more expensive version and it takes up space in the catalog(note that 21" cabinets are not in the catalog). All you would need to do, is return the drawer interior, drawer front, 21x24" door and the akurum drawer partition. Ask the co-worker in the kitchen department for a 21x30 door and you have a corner cabinet w/o a drawer