16K to Spend. Help me make the end all Upgrade.

Aerial 10Ts can spoil you because you can pretty much
plop them anywhere and get a friendly sound without
too much boom/sizzle/glare/shrieking/etch or other
audio 4-letter-words. Wilsons and others take a lot more care.
I mention this because I also had the 10Ts driven by the Pass X350 (nice liquid, rounded vocals, a bit small, but fine anyway).
If you're buying new,
you could try to audition some of the speakers that offer home trials where you pay only for shipping if you return them.

Watt Puppies are a completely different experience from the Aerials.
(I went from the 10Ts to the WP6s for a while.)

Well in my search I'm going to audition Avalons in the next couple of weeks. An interesting turn of events is that I've found somebody that's really surprised me with his knowledge and understanding of speakers. We've been talking today about building a very efficient speaker system built just for me.

Lots of folks can surprise us with knowledge and understanding of speakers. But without passion, resources, business acumen, manufacturing skills, patience and luck, they will just amount to one of hundreds who've gone out of business building speakers. If you go down that road, assume that 75% of your price has been gambled, because resale value is almost nil, regardless of the speakers' merits. That puts the achievements of Avalon, Merlin, Magnepan, Vandersteen, Thiel, et al in rarified air. Even often immortalized desginers like Albert Von Schweikert have folded their companies. IMHO, if you want custom work, redo your kitchen. Cheers,
Spencer

I agree with Sbank.

There are many (but let's just say ten for argument's sake) companies that are at the top of the hill in speaker fabrication. You have already listened to a few and have found some don't suit your taste. How the heck are you going to design and build just one pair that you know the other companies haven't been able to build and reproduce music the way you want? Impossible.

Take the $16K and 'invest' it in Las Vegas. You'll have better luck and those odds suck.

Amen to Fredericks comment. How on earth can you get a pair of custom speakers made in that price range and not know EXACTLY how they will sound in your room. Crazy.
By the way, you really should have a listen to the Sonus faber GUARNERI MEMENTO's for a delicious and seductive intro into music making at it's finest. For your room they would fit like a glove and look absolutely stunning in the gloss graphite finish. Then get a REL Studio sub to finish it all off. Bigger is not always better. You should of course find a dealer that you can work with and set whatever you are getting up and helping to find an amplifier that works with whatever it is you are going to end with.