Anderson Silva and GSP have largely cleaned out their respective divisions. When fighters reach that level they ean the right to challange warriors from other weight classes. In the meantime, they maintain their responsibility to defend their belts in their own weight classes.
GSP is set to fight BJ Penn in January. Regardless of the outcome, GSP would be ready by March/April to defend his title against Thiago Alves. If GSP wins, he can next face Anderson Silva at a catchweight for undisputed pound-for-pound champion of the world. Back at Welterweight, there is a good chance Jake Shields will be signed to the UFC and fast-tracked to a title fight. All other top-ranked welterweight - Hughes, Serra, Fitch, Koscheck - have already suffered defeats at the hands of GSP. If champions have been usurped in the Middleweight or Lightweight divisions, GSP could face them. GSP has even hinted at a desire to take on Light Heavyweights, eventually.
Anderson Silva can be matched up against Chuck Liddell in January. In March/April, he could take on a recovered Okami for his rightful shot at the Middleweight title. The epic Silva vs St-Pierre fight can take place in June/July. If Michael Bisping defeats the winner of Henderson vs Franklin, he can have the next shot at Silva in Oct/Nov. Assuming Silva wins all of these fights, he can then take on the Light Heavyweight Champion. That would be one of four men: Forrest Griffin, Rashad Evans, Quintion Jackson and Wanderlei Silva. This might be the UFC fight of largest ever proportions. And if Anderson Silva overcomes this challenge, he could take on the UFC Heavyweight Champion - Randy Couture, Brock Lesnar, AR Nogueira or Frank Mir - for his final fight before retirement.