Palin/Ryan?
It’s way too early for this exercise, but you can start to see the standard factions in the grouping. Romney appears to be in the lead right now because he’s drawing from 3 of the 4 basic groups - establishment conservatives, RINOs, and fiscal conservatives. You can see his non-RINO support starting to bleed out - establishment conservatives already moving to Newt or Pawlenty, and fiscal conservatives just beginning to migrate to Barbour or Daniels. Huckabee and Palin are splitting the plurarity (but not majority) social conservative group.
At least this set is better than 2008’s, where the various groups’ preferred candidate were all essentially RINOs on the other groups’ issues (except Fred and some minor candidates).
If I had to guess at this point, I think we’re most likely to see Barbour get the nod. He seems the most acceptable to the non-RINO factions within the party. Barbour will probably go with another governor for veep - most likely Daniels or Palin (probably whichever of those two drops out first and endorses him).