The Midrash Project at the Schechter Institute of Jewish Studies is publishing a series of books on midrash, including critical editions of at least eight midrashim. The series is edited by Profs. David Golinkin and Shamma Friedman. Each critical edition presents the midrash based on the best manuscript, and includes selected variant readings, reference to parallel sources in Rabbinic literature, and a critical commentary.
These are the books from the series that have been published so far:
Legends of the Jews by Prof. Louis Ginzberg, three volumes plus an index volume, second Hebrew edition, edited by Prof. David Golinkin, 2009.
Midrash Shmuel, edited by Prof. Berachyahu Lifshitz, 2009.
Midrash Hadash Al Hatorah, edited by Dr. Gila Wachman, 2013.
Midrash Esther Rabbah, edited by Prof. Joseph Tabory and Dr. Arnon Atzmon, 2014.
Midrash Kohelet Rabbah 1-6, edited by Prof. Marc Hirshman, 2016.
Ruth Rabbah, edited by Prof. Meron Bialik Lerner
Eikhah Rabbah, edited by Dr. Paul Mandel
Shir HaShirim Rabbah, edited by Dr. Tamar Kadari
Midrash on the Repentance of the Prophet Jonah, edited by Dr. Tamar Kadari
Midrash Kohelet Rabbah 7-12, edited by Dr. Reuven Kipperwasser