Or maybe NHT dropped them, who knows? But the Sound City and 6th Avenue are mass market retailers and I would imagine Evolution is not as easy to sell to a customer as they are multiple boxes with outboard amp/crossover so you have to be an educated owner as well. Big stores tend to go for quick, easy sales, not high-tech, time intensive sales. Why doesn't Best Buy carry Mark Levinson or Genesis? Many mass market companies have *tried* to sell higher end gear and have failed miserably at it. If Sound City and 6th Avenue couldn't sell NHT (or were dropped), it's no big surprise to me. Or it could be as simple as NHT not being able to whip out 500 M6s at the drop of a hat. Or that they aren't attractive enough, despite being very narrow. Quality is the *last* thing with which big retailers are concerned.
There are quite a few towers with 12" or larger woofers. Definitive, B&W, and many others build them. Granted, fewer and fewer as towers have become "lifestyle" product with lots of small, ineffective woofers rather than one or two real woofers. That's why you can see a $2000 tower with three 7" woofers when it should have one or two 10"or 12" woofers.
The reality is that speakers are heading towards being smaller and more attractive. Lots of energy is being put into woofers that will function in smaller enclosures. I'm worried that on-wall or in-wall speakers will be all we're left with someday. So, I support companies that do it right, even if my speakers *are* getting smaller and more attractive. T6s *are* big, but at 8" wide, they're narrower than most high-end speakers with small, wussy little woofers. Not as sexy looking, but they just plain rock. A Honda S2000 might seem fast at first, but not after you get into a car with a good V6 or V8.
But back to digital, since it would take at least 3 of the new dual 10" digital woofers to match the output of the T6s, I'd probably have to go for at least 6.3 surround if I went this way (though 6.6 sounds kind of cool). The DSP1s are attractive little speakers, I will say that. But from what I've heard, I'd go for them if they were big and ugly.