Vandersteen, Coincident or Green Mountain

a sideways move at best. the 3's are more than goo, they are regarded as classics

Check out the Vandersteen Quattro's as they are visually much smaller and I perfer them over the more expensive 5A's. No matter how good those other smaller speakers are you will miss the huge soundstage the Vandy's throw. The other speakers will be more pinpoint in the imaging and miss out on the ambience you currently have.

So you will be changing sound flavors in a big way....Just as Jaybo says... "a sideways move at best"

One word of caution. Even though I have not heard Vandersteens I have often seen them described as warm, and maybe a bit forgiving. My experience with Green Mountain speakers is that they are very neutral and revealing. I like this (I own a pair of Europas), but I can imagine that it will not appeal to all.

The Europas are very detailed, with great micro dynamics (and macro dynamics as good as a bookshelf could be expected to have) and they image like champs, but they could be fatiguing in a bright system or room.

So I'd recommend a demo before purchasing anything to replace the 3As.

I've owned the Super Eclipse III loudspeakers for about 18 months. My amplification comes from Audio Horizons TP 2.0B (tube preamp) and VTL MB-185 Signature monoblocks (tube amplifier). I use balanced connections. I have both analog and digital sources. Here are some thoughts that may be helpful to you.
Like you, I searched for excellent loudspeakers which are not dominating. My room is about the size of yours and, on the new extender feet, these loudspeakers provide big sound without big size. I replaced Wilson Sophias with the Super Eclipse IIIs. The Sophias are beautiful sounding speakers but are a little too much (physical size and forward sound) for my room.
The Super Eclipse IIIs take time to break in (preferably 200 hrs). They are full bodied, well balanced, and detailed speakers. They are so revealing that I was led to upgrade my preamp (from VTL 5.5 to the Audio Horizons TP 2.0B). Now, I would say, my VTL monoblocks are the weakest link in my audio chain. Whenever Audio Horizons introduces a monoblock, I will upgrade to it. I believe the Super Eclipse IIIs will be worthy of that future system.
Fully broken in and with the right equipment, the Super Eclipse IIIs deliver beautiful music. I have listened to them through Levinson solid state; I prefer tubes. The sensitivity and impedance specs of the Super Eclipse IIIs make them a very easy load to drive.
I've met and dealt with Israel Blume on several occasions. I've found him to be honorable and committed to excellence. I'm so impressed by the Super Eclipse IIIs that I will audition them to you if you are near my area (zip code 95818).
One last thought: my loudspeakers are in a natural finish - not so dark as the cherry finish advertised on the Coincident website. This lighter finish also contributes to their more comfortable presence in my listening room (known to others in my home as the living room).