Can Graded Quizzes be made in layers?

I'm not sure what you want, but it might be possible to get the same effect using a lightbox.

See the attached sample. The way it is now, it uses a question slide. if you want to see a question bank in action, change the order of the lightbox triggers on slide 1. The trouble with lightboxing a question slide is that the built-in submit button doesn't show, so you have to create your own. You also have to change the triggers on the layers from "Jump to next slide" to "Close lightbox"