I have Tannoy Fusion 1's on a bookshelf in my daughters room and they sound just fine. Very musical little spks. I don't know what exactly their dimensions are, but I think they should come really close to what you're looking for. These should work well for you.
Budget bookshelf speakers FOR a bookshelf...
am looking for a set (under $600) of bookshelf speakers that will actually sound good in a bookshelf. not on top, but on a shelf with a shelf of books above and below them. max of 10" wide by 14" high. i like all kinds of music, from abba to metallica, the planets to rammstein, al dimeola to joe bonamassa. used of course is just fine :)