I've just started following the Habari feed on Tweet Scan, and it's already been interesting. I came across someone who's trying out Habari, Andy C, asking if there was a plugin for Habari to enable TinyMCE (or FCKEditor). So far, no-one has written a WYSIWYG plugin, only markup plugins for Markdown and Textile, so I whipped one up. Herewith, the TinyMCE plugin for Habari.
Feedback appreciated. Telling me you're using it appreciated.
[Update: my apologies for getting your name wrong, Andy.]