Well after researching and looking at some pictures online of classic early motorcycle designs (1910's beginning of the board track bikes) I came up with a new idea for a pedal powered cargo bike.
Realize that at the turn of the century (18th to 19th) the golden age of bicycles was changing into the modern internal combustion era and the first motorcycles (which were more common then automobiles for a while) had both pedals and an engine. By the 1910's builders had settled upon the best way to accommodate the addition of a motor to a bicycle was to stretch the length of the frame and put the motor in a drop loop or box shaped area in the frame down low and forward of the pedal crank. Putting the extra weight of the motor (substantial for those early low power to weight ratio engines) in this position on the bike gave it the best handling.
So why not use the same kind of frame design and put a cargo box in place of the motor? Was the best spot and way to accommodate the additional weight of the motor on those early motorcycles which were basically just adding a motor to a bicycle to maintain good handling.
Here is a link to a goole image search for these early motorcycle designs: http://www.google.com/search?hl=en&s...910+motorcycle
And here is a couple pictures of modern reproductions (would be considered mo-peds nowdays):
And at least a few people have built custom pedal only bikes with the same kind of frame geometery:
So, why not build a cargo bike with a cargo box/basket/rack in the spot forward of the crank on that same kind of frame geometry set-up?
Something along these lines, which I quickly threw together in CAD as a quick concept sketch, cargo box in red is 18" x 18" x 23" centered in the frame (click on this diagram to open it full size):
Anyone seen or try to build a cargo bike that way before that any of you know of? What you think? I can hack my own frame from steel tubing and old steel bike frames, built several bikes that way so far so its a matter of interest and on the possible scale for me.