MediaWiki markup equivalent of WMD live-previewing editor? (not WYSIWYG)

What editor like the WMD editor can be recommended, but using MediaWiki markup instead of Markdown? Our site is already using MediaWiki markup, but we want a s开发者_如何学Pythonlicker editor without changing Markup completely.

Requirements include:

• live preview of formatted text underneath the markup you're typing
• a toolbar for common formatting (bold, italic, links, bullets, numbered-list, code, etc.)
• keyboard shortcuts for each toolbar button (for example, CTRL+B for bold)
• Undo/redo via keyboard shortcuts (CTRL+Z/CTRL+Y) or toolbar buttons
• works well in the usual set of popular browsers (including Internet Explorer 6!)
• open source would be preferred

I've found a few options at WYSIWYG editor, but all of these seem to be WYSIWYG editors which is not exactly what I want since full-on WYSIWYG editors tend to be bug-prone and complicated at the markup level. Instead we want a plain-text markup editor with a client-side previewer, plus some UI niceties (toolbar, undo, keyboard shortcuts) to make editing markup easier.

Since the time this question was asked, a new WYSIWYG editor for MediaWiki was developed, VisualEditor. Unlike its predecessors, it is a de facto standard. Note that purely live preview for a wikitext editor would not be much simpler than this because MW wikitext can be insanely complex so a complicated parser would be needed, just like Parsoid used by VisualEditor.