Can you cite me a single example? Surely there must be something out there on the Net you can link me too... what I have seen is either: i) explicit endorsement of this Rebbe is Mashiach nonsense; ii) silence; or iii) at best, questioning "maybe he is, maybe he isn't" -- no Chabad rabbi I know has ever affirmatively said "The Rebbe was a great guy, but Mashiach doesn't come from the dead." Does this allegedly strong anti-Rebbe as Messiah movement have a website or an organization?
Also, I've never liked how Chabad blatantly violates Halacha by trying to get (otherwise religious) Jews to adopt Chabad minhagim. Reaching out to hilonim is admirable, and I respect them for it. But why was Chabad's first outreach center in Morrocco, which had a strong Torah-observant community? And why have more than few Chabad Rabbis given me dirty looks (or worse) when I tell them that I don't want to go to Chabad institutions because I am Sephardi and prefer to go to Sephardi beit knesset? And why has Chabad affirmatively refused to recognize Ethiopian Jews as Jewish, and scornfully refused to give them any aid?