When i was in Mexico last I saw these yellow tricycles everywhere. They where used for all kinds of street vending. I wondered what models they where. Just a bit of googling later and I discover the word Mercurio on a yellow frame. It looks like Mercurio sells the Triciclo de Carga.
Then I found the HUSKY MODEL T-370 CARGO TRICYCLE YELLOW. Looks pricey and tricky to ride without a ton of stuff in it.
Check out the flickr search results for the words cargo bike mexico. It shows how creative people are with these things.
Brian C. Russell 
Very cool.
When I was a kid, we had ice cream vendors who had similar bikes that had large coolers in the cargo area.
This was outside of Chicago.
I'm sorta dreaming I could figure out a way to import a bunch of these bikes…