Anyone out there have any suggestions for a top case that will mount on a luggage rack? I need to find one. My hard luggage is usually filled up with my art supplies and books for my classes, and since I ride my bike daily (no car) I need a little more room for rain gear and to stow my helmet. I've seen one in the JC Whitney catalog for about $80 but know nothing about it's construction or durability. I don't think BMW makes a top case for my bike, either. Any ideas?