Recommend speakers for a large living room

Thanks everyone for the response. Lots of great info here. I have reached out to MBL to organize a demo & am also going to check-out Ohm speakers next week. I hadn’t thought about adding sub-woofers. Question, if I were to add 4 sub-woofers, how would that work? Is there a pre-amp that could handle 4 sub-woofers?

You may want to consider speaking with Duke (Audiokenesis).  He is a well respected speaker designer and the first to offer a consumer distributed bass array.  

In regard to adding four subwoofers, you simply run each in mono.  If you were to use the Audiokenesis Swarm system, it uses a single amplifer for each subwoofer.  My only concern with using the Audiokenesis would be if it would have enough output capability given the size of your room.  Again, Duke would be able to answer that, as he also designs systems used in larger environments. 

http://www.audiokinesis.com/the-swarm-subwoofer-system-1.html

I would put Sound lab 845's along the window wall of the sitting area. Line source dipoles will limit early reflections and Sound Labs still disperse over a wide angle. Line source speakers project power better so they will fill that rather large area better. Every where but the listening position is back ground music. The image is not as important. 

Question, if I were to add 4 sub-woofers, how would that work? Is there a pre-amp that could handle 4 sub-woofers?

Well first off this is definitely the way to go. I tried a bunch of things and going to four is so much better than anything else I have to say its the only real solution. Well, unless you go more. Five now in my case.

Connecting is easy. All the bass down where subs run is mono. But even if for some reason you want to run stereo (which I do, but not for this reason, it really is all mono) that's still easy. The options are too many to list but just to give you my example, two run off one channel, two off the other, and the fifth runs off the bypass out from one of the sub amps.

Mine use the Dayton amp, same one Duke uses and recommends. This amp has plenty of flexibility with adjustable phase, crossover frequency, level, EQ, bass boost, and bass cutoff. Duke uses one amp for four subs standard, with the option to run two. There isn't much reason to run two, the advantage is not for volume but flexibility, being able to adjust two subs independently rather than all 4 together.

Mine are 10" drivers, higher quality but similar cabinets. Doing it again only thing I might do different is go even bigger. Its just really hard to appreciate until you hear it just how wonderful really good deep bass is! Because, whatever you think you heard that was, unless and until you've heard four or more sorry, you just don't know. Its that much better.

Really low bass is so much different than the way things work up higher that it almost doesn't matter how you do it. What I mean is four self-powered subs will work just as well as four passive ones, and the four don't even have to be all the same. Mine for example, two are ported, two sealed, and one is a Talon Roc actively powered. You cannot tell where any of them are, and it all blends seamlessly with the stereo image.

I would second, or third, the Ulfberht's. They would be right at home in a room your size. Together with a distributed bass array, flat-out awesome.

Skip the others. Skip the power hogs. Ulfberht and Swarm. You can thank me later.

I think these threads are generally filled with people suggesting obscure speakers that are 1/5 the budget you have.
Big space, big speakers. I’d recommend at least starting out with some of the larger Focals, B&W 800D3, something in the middle of the Wilson range. Really it’s impossible to say without knowing what electronics you have (or want) and what music you listen to.

Sound Lab Ultimate series is  what I would recommend.