The wildest rumor in recent weeks goes to The Tracking Board which today reported that "Thor" star Chris Hemsworth has been offered a starring role in "Lionhunters," a proposed refresh of the "Lethal Weapon" franchise.
The report claims the story centers on the son of an older cop (likely Mel Gibson's Martin Riggs) who decides that he wants to join the police force. The idea reportedly leaves the door open for Gibson to return as Martin Riggs once again, albeit in a traditional father figure capacity.
The report also says Justin Lin ("Fast Five") is attached to direct, Joel Silver is producing, and Will Beall is working on the current version of the script. Shane Black, creator of the original characters, also reportedly has had input into what direction the sequel will take.
Riggs and Lorna Cole (Rene Russo) did have a baby at the end of 1998's "Lethal Weapon 4," but even if production weren't to begin for a few years, the character would still be about twenty whereas Hemsworth turns thirty this year.
Right now, treat this as pure rumor.