I'm surprised no-one has mentioned the Scriabin etudes - plenty of polyrhythms across those. There's 9 vs. 5, 5 vs. 3 (this one is my personal favourite), and numerous others I can't remember offhand.
And for the record, it was James Garfield, president for around six months in 1881 before being assassinated, who was ambidextrous and could write in Latin with one hand and Greek with the other simultaneously - not Thomas Jefferson. I wonder if he played the piano?