Can anyone think of any? For some reason, I can't. I spent all weekend in Miami, and my mind is M.I.A... ...but I need some instances when a 1 and 2 p4p fought in the past for a project I'm working on, I know those instances are rare due to weight differences. *Ring Magazine rankings, but for the most part, any will do, because there usually isn't a HUGE difference in various rankings, e.g., most lists have Pac at 1 and PBF at 2, or vice versa...
Is there an official 'lb4lb', though? I know The Ring used to do it in the 40s and 50s, KO Magazine did it in the 80s and early 90s.
Pac vs Marquez II if you consider that Mayweather was retired at the time (after the Hatton fight but he hadn't announced his retirement yet).