Dipoles are speakers that radiate to the rear about the same amount as to the front while radiating little to the sides. IOW, they radiate in a figure-8 pattern. Because they radiate little to the sides, they can be placed closer to sidewalls than speakers with wide dispersion patterns--Gallo Ref. 3s come to mind here.
Dipoles can be built with cone drivers; here are mine, altho my tweeters are not dipole...

...or with magnetic-planar drivers such as Magnepans, or with electrostatic drivers such as the many Quads.
If the $15K Jamos are a little rich for you, consider the Nemesis from Emerald Physics. Many of us heard a preproduction prototype at the '06 RMAF and were VERY impressed, as was Robert Harley of 'The Absolute Sound', as he wrote in the February issue. Clayton Shaw, the owner of Emerald, is redesigning the speaker to be one chunk per channel, using 3 instead of 4 bass drivers and will be demoing that version to the Arizona Audio Video Club in Phoenix late February or early March. Sorry I don't have a pic. RR will be c. $5K/pr., I understand. This system is digitally equalized, crossed over, and time-compensated for driver spacing, and the eq. is included in the price. It requires 6 channels of amplification but doesn't require expensive amps to sound good--Clayton was using a multichannel home-theater amp in Denver. E-mail him at
[email protected] if you're interested. (I have NO interest in this man or his product other than as a music-loving audiofool and audio/video-club president.)