Keep record of the winning and losing strikes! Show them in each player's profile, for each season and also for overall and create a column in the Standings page which gives you Cold or Warm images or something in case you win or lose 10 games in a row (the number could be changed).
EDIT: one more idea, how about merging all the games played on the site into a totally overall scheme statistics? I mean, the Cup games should count into the overall statistics, based on the current leagues formula. So like, I have 2000 points in X scheme, other guy has 3000 and we take these LEAGUE points as the base, since there were no other games played against each other before on the site. The come in the Cup games, where we use that ELO formula the same way it would be used for league games, but ONLY for the overall statistics. How would you like that?