-Dan, by the way, there are many different —and useful— space characters available. For a complete list, see here.
Unfortunately, unlike the No-break Space, these are not directly accessible via the Mac keyboard. Because of that I’ve written a custom keyboard layout that has a key combo for every whitespace character (amongst other things).
You find the download and the documentation here. (It’s made with Ukelele, a really great keyboard layout editor, and you can easily customize it further to your needs.)