Looking for a good full range floor stander

Sounds like hair-splitting.  Planar speakers are OK as long as there's some curvature?  How much curvature is needed?

The original Quads are - in your opinion - flat or curved?

Audiotroy, when you go to a large say stadium show what you see are very large usually JBL linear arrays. They are in no way point source because point source loudspeakers suck in that application for the same reason they suck in large rooms. Now, you can do the same thing with dynamic drivers such a the Near Field Pipe Dreams or the Carver Ultimate Line source. I have heard the Pipe Dreams and although capable of huge volume they could not image. I have not heard the Carvers. There are applications where point source speakers are the way to go. But as I said before Unless you want to sit right on top of the speakers this is not one of them. All this is in Loudspeakers for Dummies. I suggest you read it. As I said before, Maggie 20.7s are the perfect speaker for this gentleman. They fit all of his requirements, will do 95 dB in this situation and image much better than and point source speaker. The only reason I would not recommend is if he liked listening to very loud rock and it does not seem that he does. Another issue is that as background music throughout the room the Maggies and any other linear source dipole is going to sound more natural, less strained, larger and more powerful. It would not be unusual with some special recordings to think there was an actual person across the room singing. That will never happen with a point source in tha application. Palidin, I encourage you to find a dealer and listen to these if you can and have a look at them. They are also really quite elegant and make a great conversation piece. 
There are some people on this forum that spew off mindlessly without knowledge or experience. Taking their word for anything is dangerous and very expensive.

Oh, Martin Logans do not image any better than any other ESL or Ribbon loudspeaker. They are compromised by having to cross to a woofer usually at 250 Hz or above because the curved panel is non linear. Sanders, who designed this panel for ML abandoned it as inferior which you can read about on his web site sanderssoundsystems.com. 
As for size it all depends where you like sitting. I like being up front in the first 10 rows of a big concert and at the stage in a small venue. Point source speakers put you in the back of the hall. If you increase the volume to try and get yourself up front you get a very surreal effect of a band playing very loud at a distance. 

You have a very large space to fill with sound and you have a Bryston 14Bcubed so the power is not an issue.
If you look at the Bryston line, they have the Model T Signature speakers (which I have) and they are pretty amazing in performance with a huge amount of dynamic output.  I am using my pair in a 30x35x18 room with a pair of Anthem M1 mono's at 2000 watts per channel and it sounds outstanding.  I would seriously consider these speakers.