I just found
http://en.wikipedia.org/wiki/User:Cacycle/wikEd
Quoting from said page:
"wikEd (alpha) is an editor extension that adds enhanced text processing functions to Wikipedia edit pages. Currently it works only for Mozilla Firefox, Mozilla, and Mozilla SeaMonkey browsers. wikEd is a complete rich-text editor and comes with many MediaWiki features."
Might be interesting regarding WYSIWYG discussions.
Apologies if this is already well known (I did some quick searches but found nothing here).
--Ligulem