I am reasonably sure that both Kaladin and Jasnah aren't destined for any romantic relationships in the near future. They're both sort of broken at this point and need to fix themselves before they can form a real attachment with someone. I would reckon that we aren't going to see a romantic relationship begin/develop among the main cast without the book being focused on one of the two people in the relationship.
I'd bet money on Lift with Kaladin in the back 5 (not a lot of money, but more than even odds).
If I had to pick between established characters, I'd guess that Jasnah would be with Lyn or Rysn. However, I think Jasnah will end up more like Elizabeth I.