I had visions years ago of unusual municipal vehicles in Austin, Texas. Garbage conveyance (which after all doesn't have to travel at a high rate of speed), street sweeping, public safety (THAT one at least came true) -- could they all be supplied by human-powered vehicles? Certainly deliveries could, as these vehicles amply demonstrate. (Note: I limit this review to commercial-style cargo bikes, no kiddie trailers.)
Bakfiets: This Dutch company makes a variety of front-wheel loaded bicycles and tricycles. "Bakfiets" is Dutch for "carrier cycle" or "cargo bike". This make is apparently popular as a purveyor of kiddie-carriers for (hm, how can I say this...) bourgeois US households and even has some name-brand-recognition therewith.
Work Cycles: This is another Dutch company with a nice broad selection of designs. Their philosophy as stated on their website begins: "The bicycle is a perfect example of the beautiful minimalism the world should adopt to continue forward. We thus promote everyday cycling amongst individuals, families and enterprises.." Nicely put. Work Cycles does Bakfiets-style "child transport cycles" but also heavier-duty stuff like the "Bakers' Bike" illustrated. (Regular readers may notice a similarity to the Stockholm commercial bike I pictured earlier.) Update: the bike pictured in this section is a "Truck", made by Monark Bikes of Sweden, better known in the US for their exercise bikes.
The Dutch Bicycle Company: Another, hm, Dutch company (is there anyone other than me noticing a pattern here?) that deals in (among other things) cargo bikes. I get the impression that this company, more than manufacturers, are importer and dealers. They sell a bike (that they describe as Swedish-built) called the "short John" that is pretty much identical to the "Bakers' bike" above, and also a "long John" cargo bike (pictured).
Bilenky Bikes of Philadelphia (finally an American builder!) Full disclosure: I've done business with Steven Bilenky a couple of years back when he modified and repainted a touring frame for me. Bilenky is a full custom builder and does beautiful hand filed fillet brazing on his main frame joints. His motto is "Artistry in Steel", which pretty much tells you his choice of material. Most of Bilenky's cargo bikes are variations on a front-hauler style. In 2005, a courier named Hodari won the "World Messenger Cargo Bike Race" on a Bilenky. Go here to see a video of the race. Fun!
Bikes at Work is a custom shop out of Ames, Iowa that also has a production line of heavy-duty bike trailers (pictured). I really like the unassuming practicality of these units. (They are sized to fit multiples of Rubbermaid garden waste containers, available everywhere.) Bikes at Work also does custom cargo bikes; there's a page on their web site showing some of their "projects".
Carry Freedom: Not a commercial enterprise, but a take on bicycle-trailer-as-appropriate-technology. This is the ultimate green bike trailer, made of bamboo, and plans are free for the downloading. (Wide acceptance of the Internet didn't occur until long after he was dead, but Fritz Schumacher would have loved the Web and the dissemination of information it embodies.) If you have a source of bamboo, it's hard to imagine a more cost-effective solution. The page has a number of other free bicycle cart designs at the bottom that are worth visiting. See this page also for other community bike cart designs. Bicycle ambulances! (This gets back to some of my original visions for municipal support of human power.)
Continuing the "Appropriate Technology" theme, the Center for Appropriate Transportation of Oregon has many interesting practical hauling-cycle designs. Check out the "tri-hauler", a front-wheel drive utility tricycle that comes in a "third-ton" model! I've been fascinated by alternate-steering geometries of human-powered vehicles, and this model epitomizes this approach. I do worry a little about the torque on the steerer of this design, and I feel about this a little like I felt about the front-wheel-drive Volkswagen pickup truck, i.e., the weight ought to be over the driving wheels, oughtn't it?
Segue-ing on while maintaining the Oregon theme, CETMA Racks is a small builder from Eugene, Oregon who (as the name suggests) has made a business in heavy-duty front racks and is now offering a limited edition (and really beautiful) cargo bike. The bike looks exceedingly sturdy and well-engineered with disk brakes and, yes, what appears to be a Rohloff rear hub. Very, very nice. (The racks are nice too, if you're on more of a budget.) This is the builder you go to if you're an execution fanatic, where every detail counts.
I've seen the Danish-origin Christiania cargo trikes in London. They are reverse trikes, with two rigidly connected steering wheels under the cargo box. Very tradesman-looking, and they have a unique offering in the disability-transporting unit that will take a wheelchair passenger. These have many optional extras (including electric drive hubs) and appear to be very professionally built.
We're getting into the serious commercial side of things with Cycles Maximus, makers of pedicabs. These can also be seen on the streets of London and are very professionally made. Three-passenger capacity, space for advertising, compact off-duty storage, 24-speed SRAM rear hubs (no doubt with perfect gearing), differentials, and so on. You get the impression of an almost Darwinian, highly-evolved design for the pedicab, or rickshaw, or "pedicab rickshaw" as they are somewhat redundantly referred to on Maximus' site. Ding-ding! Get out of the way!
David Wilson Industries of Seattle makes a cargo bike called the "Borracho" which would be reviewed here if for no other reason than its name. ("Borracho" translates from the Spanish as "drunken".) At first glance, perhaps, this bike appears a little less sophisticated than some of the others we've looked at, but don't be fooled. It has a 600-lb capacity, and if I had to batter down a reinforced door with my cargo bike, this is the one I'd use with the least fear of damaging the bike itself. The braking system is notable here; rear roller brake (part of the Shimano Nexus hub) and take a look at the size of that front disk.
Fraser Cycles is a custom builder out of San Diego who has ventured into the area of cargo bikes. He's also done track, road, racing, and the sine qua non of custom builders, the back-to-back tandem recumbent. (Is there a more complicated bike, mechanically?) Fraser uses software on his website called "tiltviewer" that is easily the most high-tech gallery viewing software I've seen on the web. It's a little "too-too", I think.
Organic Engines (love that name) is a Tallahassee builder (Daniel Kavanagh) who also has a heavy-duty front wheel drive cargo trike like C.A.T. above, but I think Kavanagh's is more interesting. Firstly, it has a pivot (can we still call it a headset?) setup that doesn't look like it would break under heavy loading. Second, Kavanagh builds it as a cargo trike (platform only) or as a pedicab. Third, Kavanagh touts the pedicab as a small-business pitch, which I really like. Lastly, OE/Kavanagh sells frame sets only if you want to save a buck, and he's very upfront about costs. Very admirable. The first expression on his site is (and I quote,) "OMGWTFBBQ". What's not to like about a guy like this? (Well, I can think of one thing, and that is, he likes bikesnobnyc.)
So that's it, a not-quite-exhaustive survey of cargo bikes. I'm sure there are others out there, let me know if there's a favorite of yours that I missed.