Claudio Domenicali's comments at the team launch this morning. That said, they weren't absolutely specific other than they would be racing the Panigale for 2 more years.
"Of course, translated it into something that can be sold to customers at a reasonably, even if premium, price. So it will not be an exotic bike like the Desmosedici, but a high-end sports bike. We cannot say when it will happen... but it is getting closer, much closer."
^^^ Actual quote. This was after stating they were "seriously considering" adapting a version of their GP V4 for customers. They then followed up by asking about racing said V4 in WSBK to which he responded "Absolutely, yes"
Not quite "The V4 is here!", but about as specific as you are likely to get 2 years in advance.
There is going to be a V4....I had a good chat with a few people on Saturday and it is happening.
There could be a very good chance of a Aussie being on board as well....but that is just a rumour