What's wrong with Markdown links [1]? I'd have a hard time coming up with a better syntax than this:

    [Google][]
      [google]: http://www.google.com/
    [Google][1]
      [1]: http://www.google.com/
    [Google](http://www.google.com)

I'm not sure what you mean about double-spacing either. Line breaks (<br />) are made by adding two spaces to the end of a line. If you don't like that, try GitHub-flavored Markdown [2].

[1]: http://daringfireball.net/projects/markdown/syntax#links [2]: http://github.github.com/github-flavored-markdown/