I would think that you could bungee a pack to just about any of the racks that are out there. You will need to be carefull about the straps getting tangled in the spokes though so rap the straps up good. You may want to look into some of the more stylish "panniers" that look like messenger bags or briefcases though. Carry like a messenger bag but attach to the rack like a pannier for a more secure fit. Or do what I do and drop the bag into a pannier when I have the room.