I integrated Redactor as another editor option in Create.js a while back, but it looks a bit strange because it changes the styling of the currently active content area. Other than that it is very simple and clean!
Another valid editor option is Aloha, http://aloha-editor.org
You can use any (or even all) of these with Create, or integrate your own. The next editor I'm looking to add is CKEditor 4, as it also has an inline editing mode: http://nightly-v4.ckeditor.com/3627/samples/inlineall.html
Would be great to see some keyboard support in the future however. eg Super-B/ctrl-b for bold. Haven't tested on Windows, but OS X is lacking working functionality in the latest build
Took a long look at Aloha, but it has such a big footprint that it scared me away.
Thanks for the pointer to CKEditor 4, I wasn't aware they had an inline mode.