A little bird has pointed out that LEGO set designer Hans Burkhard Schlömer has been on Brickset.com and contributed some footnotes to the LEGO Star Wars sets he designed. What is noteworthy is the comment he included for 75182 Republic Fighter Tank - it reads "Clones need a ride too! I did this set as a quick side-project while working on a much, much, much, much, much, much larger set which is going to be announced on September 1st 2017."
Hans is also visible in the designer video for 10257 Creator Carousel which infamously had two LEGO employees being chased by a space slug while holding a MicroFighter Millennium Falcon. Guess who has the Falcon in his hand.
While both of these are certainly more circumstantial than substantial, LEGO is surely laying down enough clues that a UCS Millennium Falcon is imminent. Head to our topical discussion thread to lay down your thoughts.