I’ve put together a tool to generate a PDF from a set of Trello cards. The tool is at http://pdf-from-trello.meteor.com/ and with it you connect to Trello, choose your list and download the PDF. Connecting to Trello means clicking a button on a form that pops up to authorise the tool to retrieve data from your Trello account. The download consists of the card name as a heading and the card description as paragraphs below the heading. I used to produce a product description document from a set of cards I created with a team. Please do let me know what you think of it and the use to which you put it.