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.