OP here, with just another word of thanks.
In traveling over the weekend I had a chance to audition a few of your suggestions: The Vienna Mozart Grands and Focal Chorus 826V and 806V. Setup was not ideal (Magnolia and a Tweeeter affiliate, respectively), but I was quite impressed by all of them. They seemed to have good potential for performing well in a more carefully set-up environment. In terms of string timbre, I think I preferred the Focals just a bit, but it was close.
Unfortunately, word has come from my accountant that Uncle Sam will take up much of what I was planning to spend! So I may have to wait a while. In the meantime, my current speakers will serve well.
In fact, I didn't feel any of the speakers I auditioned were worlds better than my modest NHT SuperTwos. Scoff if you will, but these speakers perform quite well on the music I enjoy. I have been unable to unseat them from my listening room with the likes of Maggie 2.6/Rs, Spendor 3/1Ps, and a few B&W Matrix models. Each of these had their advantages, but from top to bottom, none pleased me quite as well as the NHTs. While I think the Viennas or Focals would probably outperform them in my listening room, I was reassured that the difference is probably not night and day. What I'm hoping for is a bit smoother rendition of highs (i.e., violins) and a bit better definition in the bass region.
Again, thanks so much for all your suggestions, and I wish I were in a position to audition more of your recommendations.
-Bob