Which speakers will fill 5,000 cubic ft coherently

Using outboard transformers with OTL amplifiers rather defeats the purpose. Appropriate speaker matching will make more sense and bring better results. Also must agree with Shadorne about cramming high performance speakers into too small a space. This will waste your money.
Most manufacturers are becoming very desperate for sales. Be sure to verify what they claim about their products.
I had Definitions and they are almost 12.5 inches across the front. I now have Presence which have a 14 inch baffle width.

My question for you is: If your room is so large, why must you squueze your speakers into a narrow space?

For what it's worth, the last I heard, Ralph himself was using Zu Druids.

Tube amps employ an output transformer to match the high output impedance of their tubes to the lower input impedance of the speakers being used. These amplifiers have at least two separate binding posts for (usually) 4 or 8 ohms depending on the number of windings in the transformer being used at that impedance.
OTL (OutputTransformerLess)amplifiers do not have output transformers to adapt them to low impedance speakers. Sometimes an outboard transformer like the Speltz is used to compensate for a native mismatch but, as I stated earlier, that rather defeats the purpose of having an OTL.

Regardless of claims to the contrary, you will always get better results by optimizing component matching. OTL amps are better matched with HIGH impedance speakers. This does not mean that other speakers will not work but it does mean that they will not be ideal mates for your amplifiers.

The Zu Presence weighs 80 lbs, has a 14 inch wide front baffle that narrows toward the rear at a 60 degree angle. It is biamped, highly efficient and sports a 16 ohm flat impedance curve. The owner of Atmasphere uses a similar Zu speaker with his amps. This suggests that he might think they work well as a combo. Zu has a return policy. If you keep them, you pay freight one way, just like any other speaker. If you return them, you pay freight the other way too. It's a small gamble.

Zu has a serious jump factor. Sound emanates effortlessly from the full range driver and the seamlessness of no crossover reproduction holds many of us in awe. They may not solve your problem completely but I would say they stand a better chance than most any other speaker, given your preferences and constraints.

My Definitions were 12 inches from the rear wall with no boom, no problem. However, I would still recommend the Presence for your situation. Black hardware is available and your wife can choose any color on earth. My speakers are the color of new copper tubing. Glossy and metallic, they look like old fashioned radios with their woofer lenses showing slivers of dark grill cloth. Flat paint is also available so you can match them to your sofa or your Navajo rug. Be creative.

"I suppose ideally, with an amp such as the A-S MA 2.2, it seems redundant to have a built in sub amp (the Zu)which is unlikely to be as good as the A-S amp. So a full-range speaker without a sub amp would seem to be the theoretical ideal and so far only the Coincident seems to fit the entire bill."

Despite the fevered claims of some tubaholics, there is a definite advantage to be had by using tubes above 50 Hz and solid stste below that point. There is some discussion afoot about whether newer class D designs outperform the conventional A and A/B amplifiers but very few would argue that tubes provide better bass reproduction than SS can.
Furthermore, it is certain that splitting low bass duties out of the main amplfier's assignment will improve it's ability to control the mids. That's why statement products are often multi-amped and/or actively powered.

Springbok10 -

Your request for education is refreshing. Help is on the way.
What Tvad says about subwoofer implementation, however strange, is certainly true. Incorporating subs can be very tricky,as you need to place them in such a way as to blend with the speakers you have already. Purchasing speakers with pre-engineered and pre-optimized inboard subs removes obstacles that you otherwise might never overcome. It is also advantageous to consider powered speakers which have onboard amplification and generally exclude passive crossovers and the compromises they introduce. The better powered speakers often have a separate amp for every driver and an electronic (active) crossover on hand to handle crossover points and slope assignments.
It is also advantageous to reproduce as wide a midband as possible without crossing over at all. This is usually the province of very small limited range dynamic drivers like Lowther and Fostex or rather large planars like Sound Lab or Magnepan. The former will not begin to fill your spave and the latter is too large for where you need to put them.
While we are at it, Beveridge is not only too large to fit but needs surrounding space which you certainly can't provide. Another suggestion called for Infinity Kappa Nines. These, if I remember correctly, hold a special place in the H.O.F. for hardest to drive speakers of all time. A very, very unwise choice for an OTL owner.

I'm a Zu guy as is well known but there are some other speakers that might suit your purposes. Perhaps Vandy Fives would fit.

Pick your poison. I would go for a wide range single driver midrange. Look at the classics like Ls3-5a, original Quad, Spica TC-50, original Advent, etc. All were as simple as possible. K.I.S.S.
Time has taught us (some of us) that complexity brings with it complication.......and problems.