SJSD is a nice one: http://ez.no/community/contribs/applications/sjsd_real_fckeditor_xmltext_integration.
You can also take a look at xeditor: http://pubsvn.ez.no/viewcvs/community/trunk/extension/xeditor/
Other related forum threads: http://ez.no/community/forum/developer/an_wysiwyg_editor_compatible_with_3_6/ http://ez.no/community/forum/developer/sjsd_wysiwyg_editor_based_on_fckeditor_for_ezxmltext/
