Oliver x Reyson and Valtome x Zelgius
Eddie x Mia would be pretty funny, but they don't interact at all during the story line, so it makes absolutely no sense.
Vika x Tormod would be interesting... I think Gatrie x Lyre would have been freaking hilarious.
But I could really care less about pairings, really. When fans start pairing characters, it tends to become... obsessive at times. If anything, some of the seemingly canon pairings (Haar x Jill) could have been brought out a little better. The epilogue hints, but doesn't directly confirm it.