Great job Joe.
I found an HtmlArea hack yesterday that might sound interesting to you:
The problem with HtmlArea (v3.0-RC1) is that it produces (only on Mozilla though) span tags instead of strong & em, and that means of course bye bye semantics, since what we want to do with a wysiwyg editor is create & structurate a content, not design it. Now look at this workaround…
I just quickly tested it, and it seems to work great.