The advice that most mirrors my experience comes from audiotroy. If someone come to me asking me to build a speaker for them and they had a lot of boundry room issues. I would have recommended one of two. One was nailed above. An MTM with a rug covering as much of the floor possible in front of the speakers. Next alternative would be a speaker with a wide front baffle.
When we build speakers, we use Baffle step compensation to counteract the effects of the sound that shoots around the cabinet. The wider the cabinet front the less or no compensation is needed. With a wide front baffle, it helps keep all drivers firing in the direction the speaker is facing and stops midrange reflections. Still add the rug to the floor to help floor reflections. I then would add to get a sealed box woofer or a front firing port in this case. Drape as much of the rear wall as possible. You should be able to pull in some fairly solid results.
When we build speakers, we use Baffle step compensation to counteract the effects of the sound that shoots around the cabinet. The wider the cabinet front the less or no compensation is needed. With a wide front baffle, it helps keep all drivers firing in the direction the speaker is facing and stops midrange reflections. Still add the rug to the floor to help floor reflections. I then would add to get a sealed box woofer or a front firing port in this case. Drape as much of the rear wall as possible. You should be able to pull in some fairly solid results.