A new print-css.rocks release is available with support for some new tools: Typeset.sh
As part on my work on zopyx.existdb I made some progres towards mounting arbitrary WebDAV services into Plone. With only a few changes to the current zopyx.existdb codebase I was able to connect Plone with BaseX (another open-source XML database) and OwnCloud. In both cases I was able to create/remove folders and create/remove contents through Plone directly within BaseX or OwnCloud. So this solution is the best solution right for Plone to integrate with arbitrary WebDAV services.