I've finally got a project that uses the workflow module so I've been able to justify putting some time into it. As a result, I've released version 5.x-2.0. This version of workflow works with the 5.x-2.x version of actions, which is the backport of Drupal-6-style actions to Drupal 5. Thanks to mfredrickson and JacobSingh, intrepid workflow maintainers.
I plan to add the ability to change node workflow state while adding a comment to a node before continuing with a Drupal 6 version.