By looking at what people described as their use case, there is a considerable amount of interest in a CAT (Computer Aided Translation) support tool in Drupal. While Drupal 6 could (and will by default or with a contrib module) provide a translation interface for nodes, content created in professional systems is often not translated inhouse, translation work is outsourced to professional translators. These professionals employ tools to remember previous translations, build on existing terminology and reuse what is already done. The industry standard for data interchange with these tools is the XLIFF format, for which fortunately Bryan Schnabel developed (and released under GNU GPL) some XSL transformations I was able to reuse.
All this resulted in the first implementation of XLIFF Tools, a module to export and import XLIFF data of Drupal nodes. I have tested some basic content nodes with Heartsome's XLIFF Translation Editor, and everything seems to be working smoothly, but there are probably hard edges you will be able to find if you try out this new tool. A development snapshot for Drupal 5.x will be available as soon as the build system generates the tarball.