CargoCycling.org, dedicated to "The SUV's of the Bike World" has an amazing array of coverage on bicycles designed to hold loads ranging from boxes to babies to beer drinkers:
Deutsche Post's mail bikes aren't pretty, but have super capacity and "training wheel"-type stabilizers in the front to prevent tipping under heavy loads.
The insane Pedal Pub puts up to 17 riders into service together, each of them contributing pedal power while one guy steers and everyone eats and drinks.
One of the more fascinating bikes we saw on CargoCycling was the Google Map Tricycle, loaded up with all of their GPS and camera equipment, designed to capture Google Street View footage in areas where cars aren't allowed.
See all of these bikes and more here.