I've got some photos of a fairly bulky box strapped to my rack that I can post later. They are on my iPhone, so I will need to download them on my computer at home after work.

If you google images for Nitto M12, you can probably find some good examples. One of the more interesting photos I saw was a bike with a wire basket zip-tied to the rack, making it very useful for carrying items for knocking around town. If you are considering using it for touring, the rack would be a great place to strap a sleeping bag, which shouldn't be heavy enough to affect handling too much.