If you have that much depth to work with, perhaps you could either yourself, or have a cabinet maker build a couple of finished, custom "nacelles"( which would serve as a sort of built-in "bookshelf surface"), into your wall at the appropriate locations. These nacelles would be made to dimensions such that the speaker would fit with an inch or so clearance all around. Then you could bring the speaker wires in from the back. Actually, you could make these nacelles any dimension you want, which means you could use more conventional bookshelf type speakers instead of the Voice 2, which is specifically engineered to be a center channel speaker. Of course, you would need to avoid any models with rear ports, which is kind of hard to do.
As to the Revel beryllium tweeters, I recently heard the Salon 2 as a stereo pair, and I found them to be very revealing and accurate. The Revel beryllium tweeter may be better than the Paradigm, but I don't think it is going to give you any kind of "warm" or euphonic sound quality, if that is what you are looking for. Any kind of poorly recorded or harsh CD is going to come out exactly that way.