Cost and resolution weren't issues nearly as much as weight. "Weight?" he asked. Well, you see, we scan books. ashacat in particular scans a lot of books. When you scan books you need a big, heavy scanner. Something that can shoulder the weight of a big tome and not get tippy when half the book is hanging over the side. Or (close your eyes here, preservationists) stand up to a book that's being pressed flat with a pair of big old fifteen-pound-plus full-height monster SCSI drives. (majikshop you know the disks of which I speak.)
In the end we bought a ScanJet 8200. Nice scanner. It hulks in faux brushed-metal glory on its table in the office. I'm pretty sure my coworker still thinks my criteria are a bit odd. But, sometimes you need a little mass to get the job done.