Soon! So soon! Also, there's a neat project called node-trello that uses the API, and one of their example scripts backs up all of the boards for an org: https://github.com/lmatteis/node-trello/blob/master/example_...

Data export is at the top of the 'In Progress' list of the Trello Development board: https://trello.com/card/board/data-export/4d5ea62fd76aa11360...

Now that the API is 'done', it shouldn't be long until this is up and running. More about data, privacy, etc. here: trello.com/privacy