Vandersteen-like "In-between" speakers

Thank you Zargon. I'll be looking forward to their official release. They certainly sound interesting especially the bass integration.
I listened to the model 5's in Raleigh, NC a while back driven by Musical Fidelities 308 series. The room acoustics weren't the best so it was really hard to tell anything. They sounded very similiar to the 3A Sigs + 2wq combo but with a better low end and slightly more resolution, transparency and soundstaging. Not a giant leap but better non the less. I'm sure better room acoustics would have provided better performance. There was also a room resonance that seemed to affect the transition from mid to low bass somewhat.
I also listened to them in Atlanta but they were so poorly setup you couldn't tell anything. I'd bet the bass was 10db up over the midrange. To bad dealers for the most part don't set up such fine speakers properly.
Now I'd really like to hear the 5A's!

I just added subwoofers to my 3A Sigs and the improvement was substantial. The soundstage is much more three dimensional and dynamic, and the midrange is even more transparent. I would highly recommend going this route since you already know you like the 3A Sigs in your environment.

Latest Update from Vandersteen:
I just spoke to the factory and the Quatros are going to be shipping within the next 30 days. The final price is $6,995/pair. Orders for them are already being taken by dealers. In fact, there is already a small back order on them.
Regarding technical specs, the bass crossover/high pass filter will use the same arrangement as the Model 5s. So matching it to the room acoustics shouldn't be a problem.
Cheers,
Michael

IMHO you should stick with Vandersteen, or find a speaker
with similar characteristics, e.g., dark, recessed, nonanalytical sound, because your amp tends to the lean and lively side. Maybe the Quattro will be right for you. It won't be my choice because I won't be dependent on a dealer for dialing in the room adjustments. Modern psychiatry tell us that audiophiles, tweakers, DIYers, want the freedom to move things about and make acoustical adjustments themselves. Do I want to make an appointment with my dealer whenever I move my speakers or change upstream gear? Not this audiophiliac! The high-end Vandersteens are some of the best speakers in the world. But they are for people who want to listen to music, not for the restless afflicted who enjoy the never ending search for the absolute sound.

There's no law that says a dealer is required to adjust the bass contour. Anyone with access to a RTA can do it themselves, exactly the same way the dealer does it. The manual Vandersteen provides even documents how to do it without a RTA.