Interesting thread. I have been running a design through my head for my rack and an optional addition. I use two panniers and commute well into winter. As the year gets colder, I need to bring more stuff (bulky gloves, ear warmers, rain gear etc). My panniers begin to fill up with my tools, lunch and the above mentioned stuff. I usually bring my lunch in a plastic bag, and put it in a lunch box that I leave at work; then reverse the process for the ride home.

What I am trying to design, is a simple way to utilize the top of my rack, without interfering with the panniers, so that I can easily carry my lunch box. I have used the milk crate before, but I want something a bit more polished. I want to be able to set my lunchbox on top of the rack, quickly attach it (not so easy with bungees and the panniers, which don't mix well) and have it be secure and easy to remove.

Still working on it in my head.