RG- venus 45%, serena 35%, justine 20%
W - serena 70%, venus 15%, justine 15%
US- serena 60%, venus 30%, justine 10%
in my opinion these are the only 3 players who can actually win all 7 matches, especially because they will, sooner all later, play against each other, too. I just don't see anyone else who could beat 2/3 of these, which will probably be necessary for the title. Davenport, Mauresmo, Zvonareva, Kuznetsova, Martinez etc. are dangerous but not capable of making it all the way.