I like the promo photo of the Kona, but I think the BD looks a lot more robust, which is what I think would be needed for a cargo bike. The little bags on the big Kona cargo frame don't instill a lot of confidence that it's built to haul loads. I also don't know if the Kona will accept the Xtracycle gizmos, but the BD was built specifically around Xtracycle stuff.

Another cargo bike option - bamboo


From the Bamboo Bike Project