This is an interesting thread to me, as my evolution in system philosophy was driven by a similar room problem to Springbok. My quasi-dedicated room in the basement is basically a 7'Wx7.5'Hx16'L tube. I have good mini-monitors (Sapphire XL), but trying to make them work even acceptably was nigh on impossible - getting them out into the room away from the front wall ate up basically the entire room, and even then you can't get much if any separation from the side wall. Without treating the entire room with 4" panels, I just didn't see how it would work.
Thus began my search for a better way, which lead to controlled directivity.
I ended up going the PA cabinet route, but the Yorkville U15's are pretty unique PA cabinets. As long as you're not afraid of a bit of EQ (needed in my case anyway due to the room modes from the 7' and 7.5' dimensions) they can comfortably stand beside hi-fi speakers anywhere close to their price point (IMHO, of course). Other than that, though, my approach/solution pretty closely mirrors what Bob discusses here.
-The U15's are placed directly in the corners
-First reflection points on the lateral walls and the front wall have a single panel absorber (the one between the speakers was surprisingly beneficial)
-In my case, the U15's have no BSC built-in, so I didn't need the additional eq to correct power response due to corner placement
Is this as good as having 1000sq ft of space? No, but considering the constraints, I'd say it works pretty darn well. In particular, it does do a pretty good job of presenting soundstage and imaging, which are typically tough in small rooms. It misses a certain sense of stage size/scale compared to larger environments though; the best analogy I can come up with is that it's similar to the difference between watching a 42" HDTV from up close vs a projector from farther back - same resolution/detail, same subtended angles, but we 'know' that one is 'bigger' than the other.
One thing in particular that continues to catch me off guard on occasion is how balanced the sound is out of the sweet spot and out into other rooms. This is of course largely due to the extremely uniform power response provided by corner placement. In my case the U15's are 60x60 dispersion up high broadening to 90x90 lower due to the corner placement, so there is a bit of a taper in the response. This is a 'season to taste' type of thing, but it's frequently the case that a bit of a slope to the power response is subjectively beneficial.
About the only thing I see needing a bit of clarification in Bob's description is with regards to acoustic treatment. The corner placement + controlled directivity does greatly mitigate the impact of the side wall immediately adjacent to the speaker. However, the *opposite* side wall is still a potential source of early reflections - i.e the left corner speaker bounces off the right side wall before arriving at the listening position. This obviously will depend on the geometry and size of the setup. In my case where I'm so close to the side walls, I 'needed' to place treatments to absorb the first reflection from the opposite corner speaker. This also is why the panel between the speakers helped - the oblique reflections went off the front wall, then off the opposite side, then to the listening position. It's a bit tough to judge from Springok's pictures how much of this will be a problem in his setup, though.
