I've added a plugin to the addons in the dev branch that implements SCEditor for Hubzilla with the main BBCode markup that most people use. The addon requires the most recent dev branch of core as it makes use of some newer hooks.
* Horizontal Rule
* Copy / Cut / Paste
* Font color
* bullet & ordered lists
* "Full screen" mode
* and the "Raw edit" button.
Image insert, web links, and attachments - basically anything that isn't an "editor"/"formatting" option is handled by the Hubzilla derived buttons at the bottom of the edit window (polls, comments, expiration, publish, location, etc.).
You can still put BBCode straight into the editing window for things that aren't handled by the editor (or even things that are). They just will appear in raw BBCode and won't be WYSIWYG'd..
Anyone who wants to add more features can look at the SCEditor website
. It's a pretty extensible editor, though take care to look over the Hubzilla side of things in include/bbcode.php and include/html2bbcode.php if you add functionality otherwise things won't get rendered on regular pages. This is one reason that certain features (floated div's and font sizes for example) haven't been implemented at this point. But what is there will handle the great majority of people's needs/desires.