My best experience for book reports was by oral exam in high school with a class of about 30.
Everyone has independent work and one by one you are called to the teacher's desk. He would take your book, open it up to a "random" spot and read a couple of sentences and then ask about what is going on in that scene. Hard to bull shit.
This could be modified to be like parent:teacher conferences where appointment slots exist while everyone else is doing something else (lunch, another class, maybe scheduled after hours)
With 30 kids in a class Im not sure this is possible. Oral exams scale horribly