Nice idea, but the problem for me would be the screen. I used to spend hours staring at my textbook back in the day. Hours spent staring at a backlit screen like a laptop would give me a headache (and does today, when I spend hours programming). But the e-ink offerings aren't there yet in terms of usability for textbooks. They're great for novels, where progress is linear, and bookmarks are search are rarely needed. But for a textbook, where I'm often flipping to the index, back and forth between subsequent pages rapidly, need color diagrams or big tables and diagrams (600x800 is often not enough room for a large table or diagram), or flipping to one of the hundreds of bookmarks that I've color-coded, e-ink and specifically the Kindle UI just can't do it. Tablet-type hardware might have a better chance, but at the cost of the backlight.

So if I was back in college, even though today I do all of my pleasure reading on a Nook Simple Touch, I would still buy paper textbooks.