Help: Searching for Vandersteen-like speakers...

I agree with the idea of a tube pre and solid state amp. I use an Audible Illusions with a Theta. Too much of the tube thing can be bad with the 2Ce. They will become a little over warm. If you like that sound---then so be it. Also, SS tightens up the bass.
I wouldn't drive the Vandersteens with anything less than 60+ watts depending on your room and levels.
The only speaker that sounds like a Vandersteen is a Vandersteen!
Also, if you go with Vandersteen's 2 series, I would go with the Signature. It IS a better sounding speaker. More detailed and open.
The Audible Illusions(or any good tubed pre) and the McCormack amps are good with Vandersteen's.

One other thing I forgot to mention. Of all the tube amps, The ARC tube amps to me sound best with Vandersteen's. Vandersteen told me once that Quicksilvers were good also.

There are a lot of good solid state amps out there. You would really need to decide on your speakers because some amps do work better with certain speaker loads and form a kind of Synergy.
The McCormack DNA .5 is a good choice. The Belles 150A Hotrod is an excellent amp. These are my two top choices in something you can obtain reasonably.
I used a pair of DNA .5's in a biamp for a long time with the 2Ce Sigs. It was an excellent combo with the Audible Illusions.
I then sold the Ce's and bought the 3A Signatures. The McCormack's continued to work well. Then I went nuts and bought a pair of 2Wq's and the 4-ch Theta Dreadnaught. This was pretty much a case of overkill in my room. Once set up, it sounds as good as anything I've ever heard and i've heard a bunch. But the point is that the McCormack's more than held their own in most respects.
As for your speaker recommendations, well, that's going to be tuff. The Vandersteen's are not very efficient and will not play that loud in absolute terms. They do go down in the upper 30's however. I really am at a lost for a good speaker than meets all of your criteria. To go down in the thirties with a 90db rating, it will most certainly have to be a ported design. Sealed enclosures will require more input power but will go deeper. Most ported designs really don't do much below 40Hz. Some people think they do but what you hear is the bump up before the crossover which gives an illusion of better bass than it really is---especially in the $1500 range. There are good speakers out there but they don't sound a lot like a Vandersteen. Meadowlark is a first order crossover but the Kestrel is not the speaker that the 2Ce Sig. is. Might look at the Shearwater used. I personally don't like its midrange but a lot of people seem to.
If you need the efficiency of 90+db, it's going to be tuff in that price range to get TRUE 35hz performance.
Might need to back up and look at Paradigm 100 series or even the Triangle Celius. Excellent speakers that can be found used for this money. Entirely different sound than Vandersteen but accurate speakers non the less. The Triangle has a tendency to be a little bright with solid state. You could drive it with an SET amp. It is very efficient. With all tubes, it sounds nice with extension down to about 40hz.

I'm going to chime in with one last post. DON'T believe manufacturers specs. If it is a ported design, it will have trouble going below 40hz ( not to say it can't but usually they will be very expensive). Manufacturers spec speakers with all kinds of figures and most are baloney. Your room also has a lot to do with this. I guess what I'm trying to say here is I've never seen a speaker in that price range REALLY go down that low. For example, the B&W 805 Nautilus was spec'd to go fairly low (less than 50hz). In my room, the best it would do using a spectrum analyzer was about 56hz at -6db. It dropped off like a rock after that. Most speakers in your specified price range are going to be ported as I've said before. At that price range, they will have a bump in frequency at about 60-100hz to allow them to produce much at 40hz. Pull out some old Stereophile magazines and check it out.
I would go with an accurate speaker such as the Vandersteen with a genuine low end. Any ported speaker is a hard match with a sub because of the phase shifts around the crossover. A sealed design matches better with a sub.
By the way, B&W makes several lower cost subs that I would think would match up reasonably well with your 602's. Try before you buy is my best advise.
I'm of the accuracy school. It is the primary reason I use Vandersteen loudspeakers. They are accurate. I also believe in phase correct and time aligned designs. You get a lot for your money with Vandersteen because the box ain't much. He doesn't waste money on a lot of wood veneers.
I was in your position some years ago. It is a learning process. I used ported designs for a while and I will never go back. But, the biggest thing is to satisfy yourself. Listen with your own ears and make your own decision. Nobody can do it for you. Good luck with your hunt.

I will have to disagree with Phasecorrect just a little on the loudness thing. Since I don't know which Vandersteen speaker(s) you are refering to, I can say that the Model 5 will play as loud as anyone should be listening to and then some. The 3A Signatures will play plenty loud by themselves and with a pair of 2wq subs will go much louder than a sane person should listen to. These speakers are power hungry and do require it for volume.
The 2 series will not play that loud(especially in the bass) before they run out and begin to compress. However, they play loud enough I feel.
As for bass, they can be full in the wrong setup. I have definitely heard worse. I personally think they sound pretty right when set up properly. However, the subs do improve things quite a bit when set up correctly. Not more bass but tighter, more controlled bass. With the low bass filtered out of the speakers, imaging and transparency really go up. Speed in the bass with the Vandersteen's, I think, is masked by the level sometimes making them sound a little plodding. This level is related to setup. Wrong room or setup and, yes, the bass does need help. But that's really true of any speaker. There seem to be a lot of lean speakers out that with no real deep bass extension selling for some big bucks. The Vandersteen is a very reasonably priced speaker that does give true extension.