The rumor comes from Ain't It Cool News, who claim to know about a Marvel-style stinger at the end of "Fast and Furious 6." You should probably stop reading if you don't want to know the secret.
So, here it goes...
According to AICN, the final scene of "Fast and Furious 6" will not only reveal the villain for the seventh film, but also place "Tokyo Drift" firmly in the chronology of the series. (Thank God.)
After the newest movie's happy ending, we get a scene that seems unrelated. Some sort of elaborate car crash takes place, and one of the vehicles is the clear winner. The victor gets out and approaches the loser's over-turned wreck.