Lots of detail, great imaging, not much bass?

I recommend auditioning the GoldenEar Aon 2. They retail new w/warranty at $800/pair, so you can probably get them within budget, but they need stands.

They are a good match for your needs in several ways, including your driving electronics:

o Unlike most small speakers, they are fairly sensitive at 89 dB. The passive preamp shouldn't be a problem to get reasonable listening levels.
o Their recommended amplifier power is 10-200 watts, so they can absorb a lot of power from your Classe amp.

In addition, they have a fast but extremely smooth folded ribbon tweeter responsive out to 35Khz. This indicates a very fast rise time, which translates into upper treble detail that helps define images and soundstage, not to mention getting the full spectrum of overtones that define timbral accuracy. The GoldenEar tweeter is a revelation; it is so devoid of overshoot and ringing you'll realize how much of these distortions we've been trying to ignore up to now.

The bass/mid driver is likewise very fast and responsive.

The front of the speaker is small and tapered to make for better imaging. The cabinet has no parallel lines to minimize cabinet resonances. All these factors contribute to better detail and a lower noise floor.

They are capable of good bass without being gassy, and stand-mounted speakers will not leak bass to the neighbors as easily because the bass waves won't be reinforced by--and travel along--the floor so much.

Rave reviews abound for these speakers. Many are for the big brother Aon 3, but they share the same design and exact same tweeter. They are also widely distributed so you should have little trouble getting auditioning them. When you do, however, make sure the dealer hooks them up to high quality electronics; the speakers are so affordable some dealers hook them up to a mass market receiver, and when that happens, the Aons reveal the shortcomings of the receiver.

06-02-13: Nonoise
I just got back from the Newport Audio show and if you can stretch your budget another $100, there was the Martin Logan Motion 15 that made more than adequate bass and sounded pretty good for a monitor. Actually more than pretty good. ...

The sound attracted my from out in the hall and at first I thought it was their electrostatic panel speaker with the built in sub playing.

The Martin Logan Motion series uses the same type of folded ribbon tweeter as the GoldenEar products. This is a very extended and natural sounding HF transducer, and works well in both products. Emotiva also uses them in their powered monitor Pro series, but since you have a Classe amp, I didn't mention them. Point being that this 21st century realization of the Heil air motion transformer is gaining some traction in speaker design.

Other than the $700 budget, the OP's requirements practically scream for the KEF LS50. Stereophile rated this a Class A (limited LF) recommended component. This is unprecedented for a $1500 (list) speaker. Basically it is a true Class A performer from around 80 Hz on up, and with the inherent dynamics limitations. But in everything the OP is looking for--clarity, detail, imaging, soundstage--the LS50 is just about state-of-the-art (according to the reviews).

As for whether it has too much bass for his room, you can't know that until you try it. The LS50 may have been too bassy for Seikosha's room but not necessarily for the OP's.

As for bloated bass in a ported speaker, that's pretty easy to attenuate--stuff a sock in it! Or, more accurately, roll up a small towel or wash cloth and put it into the port. You can attenuate the bass by how loosely or tightly you stuff the port and also by how far you place the speakers from the wall behind them.

And if you shop around, you can get a pair for close to your budget.

Read the Stereophile review. They compared the LS50 side-by-side with the Rogers LS3/5a and B&W CM5 and they exhibited more clarity than the Rogers in upper bass, less total bass extension than the CM5, but equaled or bettered both in imaging, soundstage, and midrange, especially in both male and female vocals. Reviewer John Atkinson said in part:

At the start of the review period, I was in Los Angeles producing the vocal sessions for the opera Cooperstown, composed by Positive Feedback Online contributor Sasha Matson. At the end of the review period, Sasha sent me a CD with some test mixes. Listening to our two sopranos, Julie Adams and Carin Gilfry, and comparing what I was hearing through the KEFs with my memory of what I'd heard live at Bill Schnee Studio, I would go so far as to say that the LS50 is one of the finest speakers at reproducing female voices that I have heard—for less than what you can pay for a set of high-end interconnects!