Matt, first of all, thank you for this wonderful and very informative thread. I have been following your thread from day one and I must say this is by far the best thread on any audio related forum that I have come across:)
Anyway, I don't know if you have heard about Coincident Speaker Technology. Their speakers, although normally associated with low powered tube gear, can also be driven by powerful transistor amplifiers. The floor standing models have 12'' side firing woofers, so are quite narrow in size and flexible in placement. You can place woofers inwards or outwards, it helps eliminate standing waves and can be of benefit in your room. I currently have Antipodes DS Reference, Lampozator, Coincident pre and power amplifiers driving their second from the top floor stander, Total Victory V roughly in the room of the same size as yours, and have absolutely no issues with booming bass. The speakers just disappear, the sound is neutral, but at the same time is very revealing and detailed, the bass is simply amazing. I know, they are rear ported, but side firing woofers may negate the issue in your room.
Given the caliber of the speakers you are looking at, I think, you should give their top model, Pure Reference Extreme, a try: http://www.coincidentspeaker.com/Pure-Reference-Extreme.htm.
The have separate enclosures for the mids/highs and the woofers, are full range and have simple first order crossovers. Another advantage: having separate enclosures gives additional flexibility for placing them in a room. You can even get stands for mids/high module and place them separately from woofers.
