No clue when one would be likely, though this would seem like the right time of year to do it. But with Phil Holmes running the Magic Kingdom like he is now, I suspect it will be years before the Jungle Cruise ever gets a decent refurbishment.
For some reason, I'm getting flashbacks to the ill-conceived September 2010 announcement where they unveiled "Let the Memories Begin". There was such high expectations for an announcement (or even acknowledgement) regarding the Fantasyland project and we wound up with an intoxicated Tom Burgeron, an embarassed Tom Staggs, and a redundant ad campaign.