What Audiokinesis said about large speakers. I like my Altec Model 19s (I know, broken record) in a small room. Another American in Japan with Model 19s seems to think the same thing - they go well against the back wall and almost out to the edges of the room. Duke (Audiokinesis) may be able to confirm that Altecs would work well in such a space. While they are big, the fact that they don't need to be pulled out from the back wall (though the boxes themselves are more than 18" deep), or in from the sides means that they take up less space than you'd think - also counterintuitive. A real musiclover's speaker. They roll off a bit in the treble, but the mid/treble driver can be replaced with a BMS unit with relatively little effort I am told.
They don't meet your price target. They are a lot less.
And if those are just plain too big (and they are big - though they look somewhat mid-century furniture-esque with the grills on), you can try Model 14s. K-horns might work as well, but they aren't small either.