Dear Mr Kaplan,
My relative Rabbi Reuven Brim of Bnei Brak has written (in my humble opinion) an extraordinary book 'Lemalah Bakodesh' about the Ullmann family tree. The first 'famous ullmann' was Rabbi Shimon Ginzburg-Ullmann, whose son R' Eliezer married the Rema's daughter.
I hope that helps.
I am interested in genealogy. if you have any info, I would be pleased to hear from you.