Today, the YUI team released version 2.3.0 of the library and it contains my Rich Text Editor. So I decided to build a plugin for WordPress that allows you to use that editor for blog posts as well as comments.
You can download the plugin here.
You can demo the plugin here: http://rte.davglass.com
The posting and comments feature of the plugin has also been activated, you can test the post editor by logging in with the username and password of: rte
Please be nice with the posts and the comments or I will have to turn off the demo.
I have the plugin installed on this site, so you should now see it in action when you make a comment :)