Speaker for my system around 10K$, used.

@andy2 .........................mine are in a 15 by 18 room. The bass is adjustable and the speakers are only 6 1/2 inches wide in front and around 10 inches in the rear.  They take up no more space than a pair of stand mounted speakers.  

Check out the Charney Audio Companion with Voxativ AF 2.6 drivers. Wonderful layered engaging sound with no need for a sub! Your room is about the same as mine and I get plenty of real bass from the AF 2.6 driver.

http://charneyaudio.com/

@andy2 .........................mine are in a 15 by 18 room. The bass is adjustable and the speakers are only 6 1/2 inches wide in front and around 10 inches in the rear.  They take up no more space than a pair of stand mounted speakers.

OK, but you have to convince the OP, since I don't have 10K :-)

I’d recommend Joseph Audio Pulsar monitors for your size room.  They are among the best imaging/soundstaging speakers available and will portray layers of sound if they’re in the recording, and they also pull off a disappearing act that bests just about everything out there.  

Another lesser-known option might be the Boenicke W8 made in Switzerland and would also likely work well in your room as it’s a modest-sized floorstander.  It also appears to have excellent imaging/soundstaging and has a rear-firing tweeter that adds to the openness of the sound, and it employs a 1st-order crossover that probably also contributes to the W8’s 3D imaging capabilities.  I believe it’s around $7500, but you’ll want to add the optional Swing Base that contributes significantly to the sound, so that will up the price quite a bit.  Hope this helps, and best of luck in your search. 

What kind of volume do you listen at?