What could be instead of side walls?

Can't agree with Oz's suggestion about introducing side panels, but he's absolutely right about your speaker separation. A chaotic, out-of-focus stage as you described would definitely result from listening at only 5' away while having a separation of twice that much. Try to move your listening position at least a couple of feet farther away if you can without positioning your head closer than two feet from the rear wall, but in either case, do what Oz says and try moving the speakers so they form an approximate equalateral triangle with the listener, then tweak the separation from there. You also don't tell us about the speaker aiming, but straight-ahead firing will create a more diffuse soundstage, while toeing them in to point more at your ears will increase focus. In addition, in a floor covering of some kind is very desirable to use on top of your wooden floor to provide some acoustic absorption, and should be placed underneath the speakers as well to break up the energy transfer from the cabinets to the springy floor (do not use speaker spikes in this situation, but mass-loading the cabinet bottoms with sandbags, if applicable, could help). If you can't get a rug to go beneath the speakers as well as in front of them, then maybe try out Vibrapods underneath, but as it is now, your floor is probably storing and releasing delayed energy, both acoustically, and vibrationally back into the speaker cabinets. The heavier weight of rug you get, the more it will help this. Good luck, and let us know what you do and what happens.

thanks for a great conversation,
as you might know that totem forest speakers have ball bearings. despite that i still use the vibrapods under these ball bearings.
my speakers are directed towards the focus about 6 degrees from normal.
to place them closer to each other i face different problem where i have a 2ch home theater with modest 27" Sony Wega TV. manufacturers say that these speakers are shielded but moving them too close to the TV screen does create screen distortions.

Zaikesman, I was stretching a bit on that second point. Depending on the back wall and front wall distances, the side panels might make a positive difference (would have to work out all the ratios), but I'm with you and would do that as a last resort. Marakanetz, move the speakers as close together as you can w/o messing up your TV -- every little bit helps. By the way, I'm assuming you don't have the TV or anything else in between the speakers -- that would, as I'm sure you know, also mess up the soundstage. Good luck.

Good points made here. Of less importance, but I would also add that vibrapods are not a stable mounting base for speakers and will allow them to wobble and vibrate more.
My speakers seemed to get better once a fixed a short spike and the speaker sat firmly on all 4 spikes.
Mapleshade Records recommends 2" diameter brass cones to transmit vibration out of the speaker. You could use granite, etc. blocks for the brass cones to sit on.

You are perfectly correct as far as that goes, Cdc - and that's just the problem, when it comes to springy suspended wooden floors. Many speaker manufactures will specify in their owner's manuals that the spikes should be omitted in cases like this. Rigid coupling of the speaker to a non-resonant substrate, such as a poured concrete foundation underlying a carpeted first-level floor, is of course the ideal situation. But when it comes to a flexible, resonant floor like the one Marakanetz seems to be cursed with, attempting to break the mechanical coupling is about all one can try to do, as it will sound better this way even if it means the speakers are then not quite as rigidly positionally fixed in space while the music plays (which they wouldn't entirely be anyway, if the floor they were fixed to was flexing along). You do not want this type of floor acting like the soundboard of an acoustic stringed instrument, with the speaker's drivers as the strings, and the cabinet spikes as the bridge. You've got to attempt to "float" the speaker in this case, at least with near-full range floorstanders . (In my old apartment [and it was literally old], I used to fantasize about rigging up some kind of hanging cable harness to suspend my floorstanding speakers from the ceiling! Lucky me, now that I have the system set up in my new digs on a foundational substrate - when I finally decide on my speakers' ultimate positioning, I'll even be able to actually use my spikes!)