Oh dear god yes.  [Ace9](http://ace.c9.io/).  WP MEET AWESOME-FACE.

![image](https://f.cloud.github.com/assets/2453394/2382129/dd53700c-a8d8-11e3-9bd2-6926708b9f63.png)

Apparently, it's the same editor as used by GitHub! :smile:

https://github.com/blog/905-edit-like-an-ace
http://ace.c9.io/#nav=about
![image](https://f.cloud.github.com/assets/2453394/2382131/1320ab14-a8d9-11e3-833b-311bbd6d76d4.png)