What could be instead of side walls?

I place my speakers along the long axis of the room by preference. My speakers are very far from the side walls and have terrific focus and imaging.

In some of the better articles on speaker placement they suggest that you should separate your speakers as far apart as possible to get the largest soundstage, HOWEVER, when the image begins to break up you have gone too far. Since you can't get further away from your speakers (i.e. a distance equal to the speaker separation), this might suggest that the speakers should be moved closer together.

sorry for misleading.
recently i've updated my measurements and it figures that the listening distance is between 9 and 10 feet depending on how i want to sit in my couch.
the distance between the speakers is also 9...10 feet.
all i did so far, i moved them closer so the speaker drivers is closer than tv and not on the same level with tv and the audio stand and move them a-bit closer so the listening distance is now between 8...9 feet with the same distance between the speakers.
the stage is stabilizing but on several recordings is still chaotic.

Marakanetz:

If you would like to have an idea about what the situation is without the TV in between or for serious 2 ch listening, you just can place a blanket over the TV and its furniture (if any) and compare. The only this requires is to leave the bed neat and tidy again..... or if you prefer do it late at night and keep it secret!!!

Marakanetz .. I'd try sitting a little closer to the speakers, and moving them a little closer together. I have a very small listening room, and as a result I sit only 5 feet from the plane of the speakers (roughly 6feet from the cones). The speakers are placed about 6 feet apart. The room is 10X12 with the speakers about 3 feet from the rear (short) wall and with about 2.5 feet on each side of the speakers. The imaging is wonderful, and the two drivers seem to blend just fine, even at my marginal listening distance.
My speakers are heavily toed in, facing me as I sit. I have done this to minimize side wall reflections, which I believe are the source of all imaging problems.