So are main characters are:
Ash
Misty
Brock
May
Max
Dawn

Supporting characters:
Steven (Hoenn)
Cynthia (Sinnoh)
Steven (Orange islands)
Harvey (Hoenn)
Ricky (Sinnoh)

I think:

Ash/Misty
Harvey/May
Dawn/Ricky

I personally think that Cynthia/Steven would be kinda cute because they both love pokemon and fossils and that kind of stuff. They also are both really strong trainers (Cynthia's the champion, for cryin' out loud!)

So what do you think?