Have you tried “Fullscreen Text Editing”? It’s the square icon with four outgoing arrows, next to the “Kitchen Sink” icon. Clicking the Fullscreen icon takes you to a clean page with a text editing toolbar.
Type as much as you want. Just hover your mouse toward the top of the page and the toolbar shows up again. It’s pretty handy. I find it easier to work with long posts in Fullscreen than in the standard screen with all of the other boxes (Publish, Format, Categories, etc.).
Oops! I should have searched a little bit more! :-P
I find the full screen feature good enough for long posts, and seems it will come in handy to stay focused on writing…
Thank you very much for your advice, I guess this is it =)