I was also accepted at Stony Brook, and it caught me by surprise how early the decision was sent out. I also highly doubt they are done sending out acceptances. It seems that there are two major fellowships the department can recommend students for: the Graduate Council Fellowship and the Turner Fellowship. There might be more, but it appears that nominations for these fellowships are really limited.
Regardless, Stony Brook is known for its ability to fund all of its graduate students. The fellowships are just extra money with less teaching responsibilities. So, I am sure there are a number of places left with full funding!