Mary Ellen Hopkins is still around, and her in-person contact is Jan Krueger, right her in the southeast Wisconsin area. Here's the address to her home page:
http://www.maryellenhopkins.com/index.html. Jan still has all of her books available (she occasionally does a workshop for us using Mary Ellen's technique, as Jan is a member of the Frankly Busy Bees Quilt Guild. Jan's info is:
http://www.hearthsidequiltersnook.com/.