Hi, excellent article - and excellent discussion too.
I've combined several of the ideas above into the following :
data:text/html;charset=utf-8, <title>TextEditor</title><body contenteditable style="font-size:2rem;line-height:1.4;max-width:60rem;margin:0 auto;padding:4rem;" spellcheck="false"></code></pre>
Nice layout : whitespace, bigger font, easier on eyes.
UTF-8 / international characters compatible
It's still missing some big features though, for example :
localStorage : the code from 3lv_1 doesn't work, at least on Chrome.
This is critical and essential - it's like AutoSave. You can forget about saving, it's done automatically for you. Zero data loss.
http://a5.gg works & looks great, but you can't scroll (on Chrome) once there are more lines than screen space == showstopper
Once localStorage works, then I can start using this; will move my scratch pad from my Text Editor :)
Thanks again to everyone for this awesome thread.