There are some issues here that you're not addressing and most of them are economic. I have a family member that is legally blind and can only read with massive magnification. These CCD units are great but they cost thousands of dollars. Admittedly, it's a limited market but the manufacturers price the units assuming that some state or federal agency will be buying them - not the end user. They are dead simple with today's technology but still are priced like they're wired with gold circuits. If someone can find a supporting government or non-profit agency to help them, then they're good to go. Otherwise, they need to cough up a big chunk of cash which isn't easy for someone with very limited financial resources, as most visually impaired individuals tend to be.
Ebooks are expensive. Large print books are expensive and very, very limited in availability. Traditional lense magnifiers often do not provide adequate magnification or do not address the visual difficulty sufficiently.
When I was first looking at purchasing one of these units I was seriously outraged at the prices charged for a system that has less than $100 worth of hardware. They are essentially little more than a simple flat panel monitor, web camera, LED light and some light image processing software (invert, color masks, etc) on a stand that allows the book to slide around. I would absolutely *LOVE* to see someone come up with a good system for putting a webcam and small system together for reading - it would be great to open up the opportunities for people without the means or assistance to get a reader and, almost as wonderful, would be to put the screws to these companies that are charging such a ridiculous markup on the hardware. Unfortunately, the quality of web cameras isn't that hot but maybe there are some exceptions. I wonder if this could make for a cool Raspberry Pi project.