I've taken some time to implement the first steps towards having Drupal plugin support for jWYSIWYG.
I've tested it with the Teaser Break plugin in Firefox 3 so far and it looks good.
There's no support for Dialogs yet (allthough the Image Assist button shows up if enabled, it does nothing).
I've stared myself blind at this and need someone else to look at it to see if I'm heading in the right direction.
The attach method is huge because everything needs to be done before jwysiwyg is initialized, and almost every setting is passed as a parameter.
I hope the code comments will give some pointers to what happens but if those are not enough, just ask away here or on IRC.