Today I hauled about 40 pounds of stuff home from college (on a bike that already tips the scales over 30 lbs!). I had my books and lunch things, change of clothes (I can't bring myself not to change, I get very sweaty on the ride - plus it's been warming up 20 degrees from morning to afternoon), etcetera, and
then I had 30 pounds of veggies from the organic food box program we have on campus. You have to pick the box up at the student centre, and I didn't want to bring the car just for that!
So: I scrounged up a milk-crate-like storage box and wired that to my rear rack, on top of the paired cloth panniers I usually carry (they are fairly small - I can fit books and lunch on one side, clothes and toolkit on the other), grabbed a backpack and put that in the crate, and I also dug out the wicker basket for the handlebars. So far so good except I bashed my leg on the crate as I mounted. Kind wished for a step-through frame for a minute there.
Went to class, then claimed my box and began loading. I acquired an audience as people realized exactly what I was attempting to do!
Left pannier: 3 lbs carrots, 3 lbs onions
Right pannier: books, 2 beets, tools.
Crate: 10 lb bag potatoes, 2 bunches celery, 2 lbs apples, 4 lbs oranges, a lettuce, some garlic, a lemon, a grapefruit, 4 green peppers, 1 canteloupe.
Backpack: clothes, 1 cabbage, bunch of grapes.
Basket: Broccoli, water bottle, and purse.
Ta-Da! I took a bow and rode off, not too wobbly

. All of this was in a 5 speed vintage bike. I noticed cars gave me lots of room, maybe because they thought I was insane, or maybe I was more wobbly than I thought...
Picture to come, it's on the other computer (I got demoted off the home network as apparently killing aliens takes priority).