I don't have any good examples off the top of my head. I'm sure they're out there though. I know Andre Ward has somewhat campaigned for a fight with Sergio Martinez at 168 for his belts, but it's not to the same extent.

The truth is Martinez is chasing Chavez Jr. because he is the biggest pay day available, not because he is the biggest challenge available. Martinez earns more money taking a 40/60 split with Chavez Jr. than he earns taking a champion's split against Macklin. A win over Chavez Jr. also may gain Martinez entrance into the Mexican boxing fanbase, possibly boxing's strongest ethnic fanbase, which creates dividends in future fights.

Bottom line: a Chavez Jr. fight is all about money. It's the same reason Sergio called out Miguel Cotto and Floyd Mayweather. Around that weight class, the biggest potential money-making fights are Chavez Jr., Canelo, Floyd, Cotto and Manny. The only other fighter around that weight class that has good earning potential is Lucian Bute in Canada, and maybe Carl Froch in England. Therefore, a likely scenario I can see happening is Sergio Martinez beats Chavez Jr. in the fall and then moves up in weight in his final hurrah against the winner of Bute or Froch, where he probably loses, although I give him a decent shot against Froch.