Best $10-15K bookshelf speaker?

Hands down Vimberg Amea

I just bought a pair of YG Acoustics Tor loudspeakers. They sound amazing and look amazing (my wife has STRONG feelings about speaker size). The Tor speakers are in your price band and work well with a range of amps, and in a variety of rooms -- they are 88 db, 7 Ohm sealed-box speakers (with a minimum impedance of 3.5 Ohms). I have a REL S-510 sub as well, and they blend perfectly. Reach out to Bill at GTT Audio. He's great.

https://www.yg-acoustics.com/products/tor/

Get the Paradigm Personas, they are the only bookshelf speakers I know of with dual Beryllium drivers and are reasonable priced.

+1 on the Alta Alyssa’s.  I heard them at Axpona and was very very impressed. In the end I went with Dali Menuet SEs for a bedroom system in setting up.  Less than half the cost and I love the sound of the Dali Mentor 6 floorstanders in my main rig. 

Ditto on sjsfiveo's recommendation of the Vimberg Amea. The Alta Alyssa has been recommended by at least two persons. I owned a pair. It is an excellent speaker. But, I replaced them with the Vimberg Amea, without having even heard the Amea beforehand. I rolled the dice based on reviews I had read and having heard Tidal speakers at a friend's home.  The performance of the Amea greatly surpasses the performance of the Alyssa in every aspect of music reproduction. But the Amea is approximately 2.5X the price of the Alyssa. Naturally, the next question is whether the difference in performance was worth the increased cost. The answer - absolutely!