As of now, I don't think this can be done (even via plugin). From what I have seen, and a quick search of the issue pointing me
here, Sublime Text normalizes line endings to "\n" when the file is loaded (I verified this as a file I created with "\r\n" did not contain any "\r" characters when I did a regex find). When the file is saved, all line endings are converted to what ever is specified (or opened with). I tested this by creating a file containing both line endings, opening it in Sublime Text, making some modification and saving it. So good news, when you save in Sublime, all the line endings should be consistent, bad news, you can't actually see individual line endings.