I think Alabama has the best chance of going undefeated because they play Georgia at home this Saturday. Their toughest remaining games are road games at Tennessee and LSU. I think Alabama will finish 11-1 (8-1 SEC) with a road loss at LSU, but I won't be surprised if they finish 12-0 (9-0 SEC).
Besides a road game at Alabama this Saturday, Georgia has tough games against Florida (neutral site) on 10/31 and Ole Miss (away) on 11/7. I think Georgia will finish 11-1 (8-1 SEC) with a road loss to Alabama.
Texas plays 3 consecutive SEC home games against Florida, Ole Miss, and Mississippi State, but they play 2 consecutive road games at Missouri and LSU. I think Texas will finish 10-2 (7-2 SEC) with road losses to Missouri and LSU.
So, the SEC Championship Game is likely to feature Alabama vs Georgia for the 2nd straight year and 6th time overall.