Thanks to the pointers by DITAWriter Keith Schengili-Roberts at http://www.ditawriter.com/sample-dita-files-to-play-with/, here are some resources for larger sets of DITA content for testing and development:
- Apache Derby DITA documentation: http://db.apache.org/derby/manuals/dita.html
- DITA Gutenberg samples: http://sourceforge.net/p/dita2indesign/code/HEAD/tree/trunk/dita_gutenbe...