Based on your room size, I would also consider the Vandy 5s. But you should budget for a dealer to pay you a visit and set them up. If that isn't a possibility, consider a pair of Quattros, new, at about $8K. That price should include dealer setup.
For something completely different, consider a pair of Ohm Walsh 3000s. New, they are $4K pr. Their sonics are very much what you are looking for, IMHO. They come with a 120 day in home trial, so you only lose the shipping if you return them. I've had a pair of 2000s for 2.5 years, and I can't think of a new speaker under 10K I'd rather own. You can read my review in the speaker review section. Used, might be a different story. But you need to audition before you buy, and a home audition is the best way. FWIW, your idea of buying the amp after you choose your speakers is the right way to go about it.
For something completely different, consider a pair of Ohm Walsh 3000s. New, they are $4K pr. Their sonics are very much what you are looking for, IMHO. They come with a 120 day in home trial, so you only lose the shipping if you return them. I've had a pair of 2000s for 2.5 years, and I can't think of a new speaker under 10K I'd rather own. You can read my review in the speaker review section. Used, might be a different story. But you need to audition before you buy, and a home audition is the best way. FWIW, your idea of buying the amp after you choose your speakers is the right way to go about it.