Heard only the towers before, they are.... meh. The center speaker being so small is kinda of a downer tbh - it's the most important speaker yet in this package, it's by far the worst speaker. 

I suggest you get either ELAC or QA instead. Don't have to buy every speaker at once. Just put all your money into the L/R and Center speaker first, then the sub then surrounds can be whatever. All surrounds need to be are they can play loud without crapping itself - unless you want to squeeze out that last 10% of soundstage immersiveness for an obscene amount of money.

Can you be more specific about your space constraints? Otherwise the recommendations will just go around in circles.

Better just get HTIB, there is no room even for the speaker to breath. Putting a speaker against the wall is totally off.

That's a pretty bad area to be honest. Between the stairs is one thing, but where your setup is is basically in an alcove. Bass would be boomy, mids muddy and highs would either be lifeless, echo-y or harsh (due to so many reflective surfaces as well). Your situation is quite dire. If you get small speakers, you get no bass. If you get big enough speakers for some adequate bass, it can sound boomy.

The best I can think of is the SVS Prime satellites or Prime Elevation, then get a center channel and put it on a 16" stand below your TV, then put some wedges so that you point it up towards your ears at your sitting position. That said, the Prime Satellites/Elevations don't have a lot of bass so a sub is pretty much mandatory. But looking at your area, I can't see where you can put the sub at. Maybe behind your seat(s)?

Other than HTIB towers, not really? I mean, towers are designed to be towers for a reason - to get reasonable bass without an absolute need for subs (though I kinda disagree, subs are the foundation of sound).

Actually looking at the the space again, I do think you may be able to put a pair of bookshelves with 5.25" drivers there. Are you sure the Q acoustics 3010i won't fit there? Its width is only 5.9 inches.

If you don’t want htib than will suggest you just get bookshelf speakers.

QA probably stylelaser, they always have ready stock.

SVS can direct contact maxxht or his resellers like Chong @ Actcessory depending on your locaiton.

Im gonna let go my beloved SVS Prime Satellite (pair of Premium Black Ash speaker) .. do PM me if interested 

How big is your TV? It looks like overambitious getting such a huge TV, so have to sacrifice other equipments...
Perhaps can consider bookshelf speaker with stand putting in front. I would recommend Dali Zensor 1 or Dali Spektor 2 over Q Acoustics 3010 due to capability of lower frequency around 53 Hz +-3dB vs 68Hz of QA. Dali can be audition at CMY.

I had the Anker Nebula Mars, if you ask me... it's really more for use as a projector to do presentation slides or quick, 5 minute videos. Watching a movie on it? Yeah... well. Lol. No thanks.

No matter kind of speaker is never recommended to be in a cabinet or shelf. Speakers always need to be outside. Bookshelf even should be on proper speaker stand. Center speaker is the worst when you put inside cabinet

Since you are getting new speakers, I suggest you to buy 3 identical speakers for LCR. Place them above or below the TV.

avoid speakers with tiny 3" driver

Try check out q-acoustic speakers. TV most likely Panasonic or Sony

Try check out q-acoustic speakers. TV most likely Panasonic or Sony

Mission, wharefale, Elac, heco