For a while, for the stuff that hangs out past the edges of the scanner platform, I moved a scanner to where I could stack up a pile of books level with the top of the scanner, to support the "hangover." For that scanner I eventually made a wooden box the right height, and used the space in the box to keep a ream or two of of paper handy for the printer.

My current solution for hangovers has been a new scanner with a "super B" (11 x 17") platform, so that only a few things are too big to fit.

The problem of scanning "up to the spine" in books is a common one. Some platform scanners have better "depth of field" than others, so they pick up what isn't flattened down completely, but none of them tell you anything about that in their specifications. An least some "scan manager" programs can provide some "edge compensation" that wipes out part of the distortion caused when the page is "off the surface," but the only ones I've seen with this feature require that you use a TWAIN interface between computer and scanner. Not all scanners have TWAIN drivers available since it's assumed that the users with the most money have the intelligence of a sea-slug and wouldn't be able to use anything but WIA.

I suspect that if you really want to get something to handle the odd jobs, a better choice would be one of the "stick form" hand held scanners. Scanning the widest possible path in each sweep should reduce the need for stitching and stretching what you get out of the scanner. Since I haven't tried one of these (since ca 1980) I don't have any ideas about performance, but I'd suggest you look at the ones similar to the IRIScan Book 2:

IRIScan Book 2 Here

There are several others that are similar, and I can't comment on which might be best. With this kind, you should be able to lay the book face up, so that the page is flat, and run the scanner right up to the spine. Most of these also have internal memory so that you don't have to be connected to a computer when you capture the scans, and come with "stitch" programs to put pieces together if you have to make multiple scans to capture a whole item (think newspapers, if you remember what those looked like).

Note that the same people who make the IRIScan 2 also make another one they call the IRIScan, but it requires passing single sheets through the scanner, so it wouldn't solve any of our scanning problems.

John