Right speakers for big room limited to small room placement options


My listening room is 26' x 26' with a vaulted ceiling rising to a peak of 20'.  Total area volume is 11,000 cu. ft.  I am limited in positioning speakers: must be on either side of a fireplace located dead center in the "back" wall.   L\R Speaker separation is 84" maximum, center line to center line.  The front edge of the speaker can be no more than 26" from the "back" wall.  Using Cary SI-300.2d, with Cary streamer DMS-550 for electronics.  Interested in anyone's thoughts and suggestions.  Using satellite sub(s) is doable but not first choice. 
billbouc
Generally speaking 2 1/2 way speakers have good efficiency, dynamic range and small foot print.

Where is your listening location relative to the speakers?

What are your abilities to treat the area behind the speakers and/or the ceiling?  If you can do whatever you want to, maybe some ESL's?

Klipsch Cornwall or Forte ....?   High efficiency and can fill a space like that
To get a visual, the fireplace is in the center of the wall and the speakers flank the fireplace. So speakers will be approx 10 feet from side walls correct? Would a front ported speaker fire better bass and imaging with the lack of corner/side wall reinforcement?
I've never got a fireplace flanking system to work well. I don't understand why but it just has never worked for me. I'll need a budget to make recommendations. 
Check out my setup. My room is smaller (15 x 21 x 9), but it works. For your room, I’d add subwoofers to my system. https://systems.audiogon.com/systems/4415#&gid=1&pid=1

@billbouc A: why is a bit of treatment not possible? Curious

B: check out Wilson Sabrina X small, easy to place in your constraints but surprisingly big. Add subs if desired/possible and be in bliss.