Vandersteen's, optimum placement, room limitations

I too feel your room deminsions will not allow you to get the best out of the 3A Sigs. The closer to the wall, the more bottom you will have but the soundstage will strink.
Your equipment is an excellent match. I too use the V5x with an Aesthetix Calypso preamp. Great stuff.
The best thing to do is try if at all possible. Also, you must sit 8' back to allow for the speakers to come together. This is Vandersteen's minimum recommended distance and I agree with it. Anything closer and the soundstage becomes a little diffused. You might talk to Mr. V himself about your room deminsions and the speaker. He's a straight shooter. Good luck.

As much as I love my Vandy 3A Sig's (with a pair of 2Wq subs), and as much as I'd like to recommend the 3A Sig's to you, I think the advice already offered is probably correct. My room is 13' x 18', and I think it is about as small as I'd recommend with the 3A Sig's. My speakers are about 30" from the rear wall, and about 3.5 feet from each side wall, with my seating distance about 10' from the speakers, and they perform pretty well in this arrangement. Previously, however, my listening room was about 16' x 25', and that really gave the 3A Sig's the breathing room they needed.

I'm not sure that the 2CE's will be much of an improvement from a space perspective, and their tonal balance is a bit darker and warmer than the 3A Sig's. I also doubt that the new Quatro will work very well in your room.

Given the very high quality of the rest of your system, and the size of your room, my advice is to look for a really good stand-mounted monitor-type speaker (such as the Focal/JM Labs 906) and add a good subwoofer.

Very much agree with Sdcampbell's excellent advice in your situation. A good stand mounted front ported monitor is your best bet. Avoid a rear ported design with the distance limitations behind the speakers as that will not be enough space for the rear port to sound as designed. Having owned both the 2.3's and 2Ce's, I think both need space to breathe. Some suggestions in addition to the Focal/JM Labs 906 would be the B&W Naut.805 or Sig 805, Tyler Acoustics Ref Monitors,perhaps the Ref.MM 3A de capo, although not sure if that one a rear or front port. :)

All of your feedback has been quite helpful. I should add a couple of points to clarify my position- my listening room has the speakers against the long wall, which is the only place I can put them- it's a living room about 18 feet wide. Speakers, though only 20 inches from front wall, are about 7 feet apart, and would be about 6 feet from left side wall and 5 feet from right side wall. The only other speaker I've seriously considered so far would be the Von Schweikert vr4-jr's, which I think are actually front-ported. Don't want to go to 2 CE's, wasn't satisfied w/ their sound. I do want speakers that go down to 30Hz or below; want a bit deeper bass than I get w/ my Thiels. My impression has been that stand-mounted monitors don't tend to go that low, or give a great soundstage, all other things being equal, but I'm not too knowledgeable about them. My Thiels don't sound as good as they could in current position (20" out), but are serviceable- my sense has been that Vandy's would suffer relatively more in that position... Any thoughts out there on relative sensitivity of Thiels, Vandy's, Von Schweikerts in that position, plus stand monitors that go low, w/ great soundstage? Sorry for the length here, just have a lot of questions about this...