John,
Obviously I haven't yet read any of the offline articles you cited. But I do have major objections to some of core assertions in the Swedish article:
The article states:
By choosing a corner placement you excite all existing resonances in the room and the frequency response will not become appreciable inferior compared to a completely free placement.
This will be the case ONLY IF you are lucky -- in that (1) you don't happen to have multiple different modes with resonance frequencies close to each other, which does occur commonly and will result in a big hump in that region; (2) the Q (quality factor) of every room mode is low enough so that they are all nicely tamed when overlapped with each other, without resulting in narrow humps/dips.
There is absolutely no guarantee that these conditions are met in YOUR room.
The article states:
An interesting side effect of placing the subwoofer in a corner is that the distortion is lowered significantly. The cause for this is that you get a reinforcement of fundamental tones from all the reflections in phase from the adjacent surfaces, while harmonics (which is distortion when it comes to a steeply low pass filtered subwoofer) are lacking the corner support, and become weaker in amplitude compared to the wanted fundamentals.
This completely self-contradicts the statement made earlier in the same article. You choose the corner placement with less than 1/8 - 1/10 wavelength distances from the three walls so that ALL frequencies in which the sub operates (e.g., 20-80Hz) get a boundary reinforcement. So, when the sub is playing, say, a ~20Hz fundamental, its 2nd, 3rd and 4th harmonics will all be similarly enhanced. In fact, if this isn't the case, you are in trouble because it means that you don't have a flat frequency response within the operating range.
The harmonic and other distortions generated by the sub at above 80Hz is certainly a different story. But again, as the article itself says, the higher harmonics may be cancelled or enhanced, depending on specific frequencies they happen to be at. I would in fact even speculate that this modulation may well be one of the biggest culprits which make a corner-placed subwoofer sometimes very boomy (like my own case).
In the end, the article says after all the lengthy discussions:
"...then place the subwoofer, use a lot of experimenting." 
I wish that the AUDIO articles you cited are more coherent and convincing than this one at the very least.
[added in edit]
Oh, at least I now understand the "1/10 wavelength" recommendation. Thanks! Incidentally, I play flute, which is in fact the only orchestral woodwind instrument that acoustically behaves as a double open-ended, non-conical air column. Lo and behold, the mouth piece of a flute (where the "air reed" generates sound) is located at approximately 1/10 average air-column length from the top (left) end of the instrument.
