Another option could simply be using three adequate e-readers or two e-readers and tablet simultaneously, as one would handle several paper books, exercise books and notebooks.
Onyx Boox M92 Multitasking
http://www.youtube.com/watch?v=jDm9V1PuDlk
Sony DPT-S1's tabs for multiple opened pdfs and pdf notebooks.
http://www.youtube.com/watch?v=SIcL1nz9-ME
Android 4 based e-readers like Onyx t68, M96, future i86 could also be worthy of giving it a try.