Jedhartman,
very interesting post (at least for me). Me too, I've a very small room, even smaller than yours, a rectangular "cubicle" of 12.80 x 9.70 ft. with a 12 ft. ceiling (old Florentine building).
One of the larger walls is entirely occupied by a bookcase (plus chimney); the speakers, currently a pair of (superb) Quad ESL-2905, are placed along this wall. In the middle of the opposite wall (and, thus, behind the listening position) there is a 5.25 ft. archway, which, as in your case, seems to help with bass - no boom problems either, at least with the Quad's. (Of course, the Quad's move very little air, but I had a pair of relatively small B&W's before, placed quite close to the rear and side walls and, well, there was no boom at all.)
Now, it's quite a while that I'm considering to get a pair of Unifield's (I listen to A LOT of chamber music, and the Quad's are fabulous with that; however, when it comes to orchestral music, well, there I miss some slam).
Question: Is my room too small for the Unifield? What's the minimum distance they should be placed from the rear and side walls and from one another? And what's the minimum distance from the listening position?
Thanks for your help.
Ciao,