I'm looking forward to that too, but they did make the comment that they know there are some high expectations for the upcoming camera and they want to get it right. With that in mind, I would bet that they'll hold their cards close to their chest until its pretty close to ready to go. I'm going to bet acknowledgement of a higher end body in their pipeline is as close to a development announcement as we're going to get.
I would expect that they want some sort of hook from a marketing perspective to push the body. For instance, the R boasted the best low light focusing, the RP was lightest/cheapest to date, and I'm sure they'll want something like that for launch of the pro body. The issue with development announcements is that if they come too early, their promises may not align with reality in the end.
At the end of the day, I think we can be confident that Canon is going to offer a higher-end mirrorless camera because they've left the high-end price bracket alone for mirrorless. I can't see the EOS R being their most expensive mirrorless body they offer when they know people will pay over $3600 for a camera like the 5DsR. That's not to knock the 5DsR, it's just a note that Canon is a lot of things, but cheap isn't one of them! If Canon thinks they can get over $3k from consumers, they're going to try.