Tito, Just some comments from experience but not directly related to your request. I have scanned a fairly large number of documents (mostly thin brochures in which the staples could be removed) using a low-cost flatbed scanner. The one I use is in the Canon LIDE series - these use LEDs and work off USB power (no additional powercord). They are quite inexpensive (around Rs 3000) but slow (like all flatbed scanners). It is useful if you are doing high resolution scans of images. If your focus is more on text - and it readability or OCR-ability  - then a digital camera based rig works much more efficiently. Lots of sites on DIY book-scanners (and you can probably get Viswaprabha to demo you Scantailor). For library research purpose copying I routinely use a small pocket digital camera and it does a perfectly good job. Most librarians I have met have been ok with their use.