Calypso

 Calypso  is the javascript-based rewrite of the WordPress admin interface for WordPress.com and JetPack enabled blogs. It relies on the WordPress.com REST API to communicate to the WordPress core. It provides desktop apps for Mac OS X (10.9+), Windows (7+), and Linux (.tar.gz)/Linux (.deb)

It's open sourced on Github.

Criticisms
Even though the admin interface is not something the has to be curlable, a JavaScript-only interface with no fallback is not a friendly solution for everyone.

It requires an account on WordPress.com with JetPack enabled.