Syntext Serna
"With Serna, general users and professional authors alike can create and maintain complex XML documents. With minimal training, most people will find it as easy to use as a conventional word processor.
[...] Serna is unique because it allows users to edit documents in print appearance , thereby greatly simplifying and shortening the document maintenance cycle. Having print appearance means that users have a real view of layout, section numbering, TOC, data merged from other documents, etc.
Serna uses the most prominent open publishing standards of the day: XSLT and XSL-FO during the whole authoring process. Most other editors which claim to be WYSIWYG use simple (often proprietary) stylesheets which provide only a limited view of the document, usually very different from the final presentation."