A number of times recently I've had the idea of preview-ability for different XML formats come up. Komodo has a simple browser preview built into it, and can show the preview in a split pane. It occurred to me that CSS could be used to do something interesting with the preview, so I wrote up an article about it on our community site. I think one thing this points out, there is functionality in Komodo that we did not intend or plan for, it's simply cool stuff that is available because of the wonderful work that all the Mozilla contributors do. As an extended example, try out some DocBook editing in Komodo, along with some CSS from http://www.badgers-in-foil.co.uk/projects/docbook-css/ I'm sure this could also be done with DITA, but the Docbook examples seemed a bit easier and faster to try out.