Hi!
If you want to be requiring that your clients use a particular browser (i.e. IE 5.0 and above), you should consider using ActiveX technologies - there's a good control called DHTMLEd, which allows to edit both the HTML source and in WYSIWYG. It does an excellent Word-compatible job of it (so you can select text in word and simply copy it into the control). You need to understand some pretty complex Javascript stuff, and install addons such as Tag-cleaner, image insert dialogues, etc - all by using Javascript.
If you would like, email me and I will send you some demos - and links to sites that use this technology. It's really great.
Only drawback - you will be binding your client to a particular browser, although research shows that Netscape and Opera supporters are giving up on these products. :-(
Best regards,
Stas