We know for definite:
Heidi & Andrei substituting for Sylvain
Jennifer & Dan
Rumoured (either taken from "The Spoiler Pairings Thread" or what I've heard elsewhere):
Charlene & Matt G
Matthew & Nina
Chesney & Jodeyne
My guesses from the rest of the women:
Leila & Sean (he describes his partner like someone who's up for a laugh.)
Chemmy & Matt E (they'll give him a contender.)
Jorgie & Lukasz (a promotion for him after he was such a hit on tour.)
Which leaves Rosemary & Mark.
I'm struggling to guess at the men because I'm not so familiar with them. The only 1 I'd stab a guess at is Sebastien & Vicki or Frankie (I'm expecting they'll want him to go for some extreme routines and they're the most unconventional female pros.)
The only other prediction for the men is that there'll be some twist involving Sam & Mark, with only 1 of them allowed to continue past week 1. Maybe they've even both trained with the same partner!