Adobe FrameMaker ($1000 US)
Adobe Framemaker is a technical documentation authoring tool used by technical writers. It supports authoring in DITA format, and includes excellent publishing capabilities that make it worth using for this purpose alone.
Note: If you plan to use Codex-authored files in Adobe Framemaker, you must set the Codex Preferences to use DTDs for new files instead of Schemas. Adobe Framemaker does not fully support DITA files that use Schemas.