Speakers VERY close to wall - Cork board useful?

If you want to enable your speakers to create a soundstage, you might try diffusion behind the mids & tweeters.

I had a similar situation and found there's really no substitute for breathing room for speakers unless they're built to work that way, especially if you're concerned with soundstageing and imaging.  So here's what I did -- when I wanted to listen critically I pulled the speakers a few feet into the room and pushed them back when done.  There are probably lots of aftermarket footer options that would let you easily slide the speakers back and forth without damaging the floor or significantly compromising sound quality.  Hope this helps and best of luck. 

I think all cork will do is eat up more valuable real estate back there. 

The vents look like a good idea.

I have relocated ports, cutting out frontal ports with a hole saw. Then sealed the rear cavities. I got the same sized ports from a parts supplier that have over hanging flanges for easy installation. Plus they hid the rough cuts and small chips created by the saw. The side mounted bass may work to an advantage as to not challenge the speaker's over all design much, or at all. More true if the internal cavity is symmetrical. But I'm not suggesting anyone go hacking into there factory speakers.  

Footers for easy movement sounds like a good option. But wont help for decoupling. For carpet footers made of rounded over walnut or other choice with a high count sandpaper polish. Even hit them with some wax. This made a 150 + lb audio rack a breeze to slide away from the wall to make adjustments or dust. Then when I had it placed on a hardwood surface I simply stuck felt pads under them.

Some bass traps in the L\R and top corner should further help the situation.   

Does anybody know of the speakers Designed to be set against the wall??? I know of just two: Naim SBL and DBL but they r discontinued ;-( Anything else?

NHT, but haven't heard from them in years. Still around? Cheers,
Spencer