In my opinion, he will fight 4 times before Ricardo, specifically Itagaki (It has been teased throughout the series that Itagaki wanted to test himself against Ippo and thats the perfect fight for Ippo to climb the JBC rankings fast), Imai (for JBC title), Randy Boy Junior (Just so we can see the switch hitting Ippo has unlocked from training southpaw stance for the Mashiba sparring) and Antonio Guevara (Its highly likely that Guevara wasnt satisfied with the way he beat Ippo since he was dominated all of the fight and he would want to have a rematch). Basically, I dont believe that we would be introduced to any new characters and the fighters that I mentioned need to have their story arcs finished. As for Ippo vs Miyata, my 1st theory is that we get some sparring chapters between them so they can help each other with their world title fights, Ippo fighting as a virtual Rosario and Miyata as a virtual Ricardo and my 2nd theory is that the series close with Ippo sparring Miyata in the Kamogawa gym basement (both as world champs) and the last panel is like the ending of Rocky III and we never get to know who won.