Performer-in-Room Quality with Speakers?

If you are going the single driver route, I'd strongly recommend checking out the Omegas.  I've got a houseful of single driver designs and the Omega drivers seem to always sound the best to my ears.

Steakster,

I have somewhat mixed feelings about the OHMs for one reason (coming below). 

First the good, however.  They really do provide a huge soundstage, wide and deep. Pinpoint imaging?  Not like a high-end small stand mounted monitor or quality (to me that means not home theater geared) slim tower.  They sound very good anywhere in the room and are not especially placement-sensitive.  Everything sounds very natural and even, and I cannot imagine having listening fatigue with them.  I hear no extreme peaks in their reproduction.  They can play loud with enough power. 

And they go low, but here's the misgiving I have about them.  (They still are not fully broken in probably, so keep that in mind.)  They do deep bass but only if they are turned up to medium or higher volume. At quite low volume almost all bass disappears.  In some recordings there is low bass content I hear with my Shahinians or DCMs even at lower volumes that the OHMs do not start to reproduce until they are turned up.  When they ARE turned up, the deep bass is definitely there and does seem to be in balance with the overall music, plenty loud.  I think because of this they would probably be good in a much larger room than I have them in.  In a decent sized room, orchestral music, opera, big band, pop, and classic rock would probably sound VERY good with enough amp to get them there.  Hip-hop, techno, any electronic dance, no.

Regarding the sonotube cabinets, they are quite rigid.  A rap of my knuckles on the side produces a very high acoustic tone, right up there with the most heavily braced speakers I have ever had.  They are solid for sure.

I will probably hold onto them for a while (I hold onto gear for much too long, a habit I should lose.), but I do not know how long I'll keep them in the line-up if an extended break in does not bring out low volume bass from them. 

Michael

There is a pair of Zu Druid Vs just listed on this site. You might want to look at them. Single full range driver with a first order crossover to the tweeter. Haven't heard the Vs but Have a pair of the Def4s from Zu and they are astounding. 
The Druid Vs are known to be uncanny for presence, having better balance down low that the previous itineration. You are on to something with the time aligned prerequisite, it matters in spades.
Good luck with whatever you may choose.