Joao, last year, Jelena Dokic won her first title at the Italian Open, a tier I event but still not as big as IW.
And when I was watiching the match on ESPN (or ESPJen and ESPMen as they call it), Pam Shriver said that the lowest seeded player to ever win a tier I was the 14th seed (Didnt mention name) so I guess Daniela was the lowest seed to ever win a tournament!
azarenka - pavlyuchenkova - li - jankovic
garcia - bencic - paszek - rus - kanepi - kuznetsova - stephens
bouchard - karatantcheva - larcher de brito - voegele - lim - mladenovic
mary pierce - forever #1
vaidisova - kournikova - golovin - henin the boys - federer - gasquet - del potro - haase - nishikori
I believe Serena was unseeded when she won Indian Wells in '99 -- although there were only 56 players and 16 seeds in the main draw at that time. In fact, my reading of the draw (she defeated #2 seed Davenport in the R32) says that she was indeed unseeded.
I don't know what her rank was at the time, however.