I've been using WriteRoom for a while for all my distraction free writing needs. But since I recently decided to move to Vim (or more specifically, MacVim) I've tried to reduce my usage of other text editors.
Vim can reproduce most of the features of WriteRoom, but the only one that prevents me to switch is the "typewriter scrolling" mode. For those who haven't used WriteRoom, this feature lets you write always on the same line (much like a typewriter) so you are always focussed on what you are writing and not distracted by what you have written. All the text scrolls up when you start a new line.
I've done my homework by googling everything that I thought was related, but I only found "plugins" and other Vim configurations which are making Vim look like WriteRoom but never provided the holy feature (maybe I've looked with the wrong keywords because I'm not a native speaker).
Although I found this article saying that it's possible with a simple setting I couldn't make it work, be it in the Terminal or in MacVim... If that works for you, I'd be glad to hear how (I've started with a blank .vimrc maybe you need to active some other stuff).
This feature is not very useful when it comes down to code, so I wouldn't be surprised if it wasn't possible out of the box. In this case, if you have any leads on how I could script that (even though I'm not familiar with scripting Vim, I can look into it), then I might try to make a small plugin for that.