The WBC has just announced its mandatory challengers for each of the 17 weight classes, with the exception of the welterweight and junior middleweight divisions. Those divisions, of course, are where Floyd Mayweather resides as the current titleholder. Stating their acknowledgement of Mayweather's unique position in the sport, and citing their hopes to pave way for the ever-elusive May-Pac fight, the WBC board unanimously approved tournaments at both 147 and 154 to determine who Mayweather's next mandatory challangers will be.
Both tournaments will include the top eight challengers, in their respective divisions, who will go head-to-head until there's one man left standing. The last one standing at 147 and 154 will be named Floyd's mandatory challenger. This is essentially two "Super Six" style tournaments, with the exception that there will obviously be eight fighters, and the winners won't necessarily get the title, just a shot at Floyd (maybe).
The tournaments are expected to last a year or more (depending on how many ranked contenders are willing to participate) with the theory being this would secure enough time and space for Mayweather-Pacquiao to take place. The other caveat of all this is that by the time the tournaments are complete, Floyd will have already completed his Showtime contract and may well be retired. If he's not, the winners of the tournament will have built a strong enough resume to be considered a bona fide challenger to Mayweather.
Personally, I think it's doubtful that any contender looking for an immediate shot a Floyd, such as Amir Khan, would be willing to participate in any such tournament...but we shall see how it all unfolds.