I have done one or two books using the glass plate + camera method: camera mounted on a tripod, book opened up halfway, and a glass plate to hold the pages flat

I have done one or two books using the glass plate + camera method: camera mounted on a tripod, book opened up halfway, and a glass plate to hold the pages flat while taking the pictures. I think my workflow was 5ish seconds per page. If I were to do more and had the space, I would have gone the diybookscanner.org route to improve the quality and processing rate. At one point I belonged to a hackerspace in Oakland that had one available. Post-processing workflow was much easier, and involved using scantailor (awesome free software to batch align, crop, white balance, etc the pages) and then Acrobat for OCR.