Speaking as someone who has come to all the same conclusions as the professor in the original article, and who is almost literally standing over his bookshelf, drumming his fingers on the saw and trying to convince himself to try using it...
... the DIY book scanner is indeed tempting. But the payoff is so lousy. From what I can see, you'll tinker and tinker with the DIY scanner just to get it to keep the pages in focus and well illuminated, and to get the software workflow pieced together. Then, because you probably don't have a big budget or a machine shop, you won't get a robot that turns the pages, even an imperfect one that skips pages and occasionally mangles a book. ;) You'll have to turn the pages yourself, by hand. That labor all by itself is more expensive then 90% of my books.
Meanwhile, the Scansnap is the real thing. My favorite piece of tech gear in years. It just works. The images come out nice. My magazine pages fit perfectly on the iPad screen.
Google has done all the hard work, of course, robotics, professional book-handlers, and all. Pity that I can't access most of the fruits of that.
So at some point you just have to try and convince yourself that it is no longer 1500 and printed books are a cheap commodity. As the article points out: Publishers routinely destroy printed books. They're just ink and paper. Even most of the books you think of as priceless collectibles are not particularly priceless. The really expensive part of an out-of-print book is the ability to read the words. If you want to decorate a room in beautifully bound old books, any old book will do.
And, thanks to the economics of publishing, most of my really hard-to-find out-of-print books are old trade paperbacks printed on cheap paper. It will be a challenge to preserve these books through my lifetime anyway. Rather than wait until the things age and fall apart, I might as well take them apart myself.
And this is how I argue to myself. But still, it's hard to bring myself to use that saw. What we need is a market in sawn-up books. Just rent a copy of your rare book that's already unbound and ready for scanning. Sell it on to someone else when you're done with it. Then you can keep the original rare book (in storage, somewhere upstate) but read the text whenever you want. The fact that this (AFAIK; IANAL) is legal but simply Bittorrenting a book you don't own is not is a very clear example of the brokenness of our legal system.