/agree with Delphi.
That thing's not a textbook, it's a coffee table book.
Something like that with a couple of 10" screens would be wonderful; I'd buy it. If this fits a niche in the educational market, great; I hope it does well. The more devices the merrier. But I'll be waiting for its baby brother.
DRM is to rights management like DDT is to pest management.
Filesystems manage files. Calibre manages books. Let calibre do what it's there for, and don't go peeking up its skirt. It'll slap you. ~ ~ (explanation here