Curious what people think is the best "value" high end speaker (~5K to 15K)

A vote for Vandersteen and Revel/JBL....

I went to RMAF and there were many rooms that had one model or another of the B&W 800 series and every single room exhibited overly prominent high end. Some people like that or have hearing damage, if you like them buy them. 

The most science is probably behind the JBL and Revels. I'd get used pair of Salon2. That is probably the right answer just based on your stated requirements. 

Sanders 10e electrostat. I used to have ML CLX Art speakers with big Pass amps. Then I tried Sopras too. The challenge I always had was the room. If the room is not perfect, the "first reflection" point always messed up the sound stage for me. Roger Sanders (who is an amazing engineer, and great person) designed his speakers to have not first reflection point coming off the side walls, so it largely (though not entirely) eliminates the biggest headache I ever had with speakers. I say not entirely because room generally should have about 30% of softer wall surfaces for other sonic purposes..... same as with other speakers. Absolute Sound recently did review of these speakers, and I heard them at RMAF. Plus, Sanders includes an amp and crossover with the speakers and 100% money back guarantee. We are building a new home and will place them in our main (high ceiling) living room space. The one knock I heard on these speakers is that the sweetspot is really, really small. Yes, I get that and agree with it, but that is true for all speakers in my experience. In walking/staking  outside the sweet spot, the sound was still very good (just not epic).  On top of that, the price is quite reasonable. From what I heard at RMAF, compared to my ML/Pass set-up (which was many, many times more $$), the sound quality was quite close..... and that was in an non-ideal hotel room space. 

Tannoy Canterbury GR

MartinLogan - ESL 15A, ESL13A and ESL11A!  I have the 11As and am continually impressed by their performance.  Outstanding value!

Again I'll 2nd jkrejcii post, Sanders 10e speakers. I've heard them many times at a dealers and they are plain musical. OP try and get a listen.