The Yuba Mundo is another cargo bike option. Heavier than a Big Dummy (high-tensile steel instead of chromoly), but really solid and stable. At $1100 fully built ($575 for the frame and fork) it's inexpensive (for a cargo bike). 440 lb+rider capacity*. Lots of mount points for doodads and custom carriers. I like mine.

* For the pre-built bike, which has a rear wheel that can only be described as "unique". Your capacity will likely be lower with other wheels, but it probably won't matter for most uses.