According to the Portuguese version of Wikipedia, Ghost (the soldier of Task Force 141 who, presumably, died along with Roach in Loose Ends), didn't die and will make an appearence in Modern Warfare 3. In the page, it says: "incluindo Ghost que não morreu no segundo jogo da serie". Translated to English, it says: "including Ghost who didn't die in the second game of the series (MW2)".
So what do you think? And please, no flaming, trolling or any form of bad communication in the comments.
EDIT: As the link above doesn't show sources of what it's written, I can see that this whole blog is gibberish. Sorry for wasting your time.