emackey,
I know that Sandcastle uses CodeMirror for it’s JavaScript editing, but have you heard of Esprima? (http://esprima.org/)? Looks pretty awesome and wasn’t sure how it stacked up.
Matt
I think Esprima is only a JS AST parser, not an HTML code editor. The new versions of RequireJS switched to it for parsing purposes, but we haven’t upgraded yet.
It did look a little low-level, but there examples all looked code-editor oriented; I don’t know much about Code Mirror or the various other JavaScript code editors, so I figured I’d at least mention it.
Another possibility would be to use it to auto re-format our demo code so it’s all consistent. I don’t think Sandcastle has any auto-formatting, but I could be wrong.