Tim Spalding noted a new LibraryThing books API, intended for use for designing widgets for a browser.
I haven't dug into it yet, but what I told him is that I'd love to end up with some relatively easy-to-type URL that would let me make links to LibraryThing, Amazon, and the Ann Arbor District Library, all with a nice cover image. (For AADL I should be also able to get title availability.) It looks doable, but I probably need to write down more about that to make sense of it for anyone else.
A good example of this code in use is the CoverFlip sample app that MMcM put together.
More, I'm sure, to come; for now see the api developers group.