As Grinnell and bigshutterbug other have posted, the Reference 3A from DeCapo is a great candidate. My audiophile nephew has this and drives it with 300BSEt Tubes which is about 8 Watts. his room dimension is very similar to your room dimensions too.
I heard this and I am impressed with sound staging, palpable and sweet sweet highs. great for Jazz and female vocals are very surreal. for me, highly recommended. Also, i like to point out that Bass from this speakers are very good, well balanced and satisfying, but....
One thing that this does not do well is deep and strong bass if you like strong deep bass, you will need to supplement extra subs. In my nephew's case he has subwoofers that do this.

