Revel F208s, F52s or Nola Contenders?

Have you considered Bryston Middle T or Golden Ear Triton 1?
I'm looking at these and Revel 208 to get a little more horsepower for Zeppelin, etc.
They all appear to be ass kickers...

Dweller, Thank you. I had not even heard of these speakers. However, I have listened to, and purchased for my sister, Def Tech speakers. I think if I was to look at the Bryston, I might move towards the Model T as the Middle T was specifically designed to match Bryston electronics, according to their brochures.

The Triton 1's have outstanding staging and imaging - very holographic sound! I'd describe them as "disappearing" in a panorama of sound. Very "Maggie" like.

But... their highs are less prominent than their bass and mids - which tend to overwhelm their highs. They do sound very good... if... you aren't looking for very prominent highs - they have a smoother, more refined, sound - which was not "my cup of tea." And... you'll need room treatments, or a good DSP to eliminate the "room boom" you can get with their bass and lower mids.

I've heard several Silverline models in many different venues and all pulled off very good disappearing acts -- something that's very important to me by the way -- so I'm a little surprised at your experience. Is this with all music or just certain recordings? I also completely disagree that Silverlines sound "boxy" (have you found that to be the case at all?), which sounds more like a retailer trying to get you to buy new speakers -- go figure. I'm assuming you've experimented with placement and gotten them sufficiently away from side and back walls and that they're hooked up correctly. If it's not placement I'd start to suspect a problem either with the speakers or upstream equipment. You might also try calling Alan Yun of Silverline as I've found him to be one of the nicest guys in the business so he may well have some helpful suggestions.

If at all possible I'd try to borrow another pair of good speakers and see if you have the same problem before going to the trouble/expense of buying different speakers. Hope this helps and best of luck.

Have to add that all things being equal the quality of the recording really can determine the level of transparency which equates to speakers disappearing. I have never heard Silverline described as "boxy" and would agree that sounds like a sales pitch.