I am familiar with what the US Code says about copyright and fair use, and am specifically interested in actual practice regarding academic publications which use small amount (under 10% of the original) of a protected work, without obtaining permission. Specifically, I would like to know if an infringement suit has ever been successful when the amount of copying has been under the prevailing "substantiality" threshhold, and the copying was in an academic publication. I'm not asking what might happen or whether I should ask permission. U.S. cases and non-U.S. cases would be relevant (to the extent that "fair use" concepts exist in other systems). Alternatively, if you know of a case where the copier prevailed specifically because the use was in an academic publication, that would be relevant.
One case in a similar direction is Sundeman v. The Seajay Society. A researcher included quotations from an unpublished work in a presentation; this was upheld as fair use. There's some discussion of the case and the outcome from the Columbia copyright office (have to scroll down a little bit). There are some other related cases listed on the same page, e.g. involving fair use of copyrighted images in less academic publications.
Half an answer...
I no longer have a copy of Permissions: a survival guide (lent it to someone and never saw it again) but from memory, it discusses a few cases along these lines, particularly from the scholarly-art-monograph world.
(While the XYZ estate can't stop you writing about XYZ, they can make it very difficult if they refuse you the rights to use any of their visual artwork... and publishers get nervy about claiming fair use on things they would normally expect to pay fees for.)
Unfortunately, it's been a while since I read it and so I don't recall if any of them got as far as a legal case; I suspect the publishers usually folded. Worth taking a look if you can find a library copy, and seeing if it names specific cases, as these might be just what you're after.