It's my impression that there's "no evidence" of a new motor because nobody is talking. It's the best kept secret of the century. Nobody I know in the Duramax plant or GM Engineering will talk about it. They won't deny it, or confirm it, or release any significant information, except for teasers like the fuel and emissions programming will be in-house instead of Bosch.
So I've provided some limited media information - evidence that there could be a new block, and others in this forum who have contacts in GM have also posted notes that anyone close to the engine is not talking. There has also been a posting that the original release date for the 2017s was delayed, which a local dealer told me he also heard was associated with the new engine. So let's hear it BanksLB7Duramax, where have you looked for evidence, and what have you been told by people you know in GM?