Horn speakers with Imaging?

Most speakers can be made to image quite well--it is mostly a matter of placement of the speaker in the room and the placement of the listener in the space.  I've heard truly massive horn systems image beautifully, even in surprisingly small rooms, because someone did a great job of setting them up.  Giant horn systems may not be ideal for the "disappearing act" that is so prized, but, they can get the scale of the music to be large and realistic (with tiny monitors, even if they can fill the space, you don't get the sense that the music is coming from sources of the right size).  The directivity of horns can also help to minimize the effects of reflections from nearby walls and that can help with imaging too.  

I have not heard any system where one could say that ideal sound was available in an area that could accommodate more than a single listener.  The closest was a big room with omni-directional MBL speakers and a giant horn system in a room that was bigger than 25' by 40'.  In both cases, if two people sat really close to one another, the sound was pretty good for both.  In my own system, even a few inches of movement one way or the other des affect the sound, particularly the imaging.  My system does emloy a horn for the midrange compression driver.

Extreme toe-in creates a larger sweet spot because the speaker that is farther away is actually closer to being on-axis, which compensates for the additional distance.  The down side, I find in most cases, is the sense of width and an enveloping soundfield is diminished a bit.  Like most things, every choice has a trade off.