I can think of three designed-for-corner-placement speakers in production that I really like. From smallest to biggest:
First is the AudioNote AN-E... very warm and easy to listen to. I am among those that raise an eyebrow at Audio Note's claimed specifications, but that does not lessen my respect for their speaker's sound quality. In my opinion the E is an exceptionally well-engineered design. I have not heard the J's placed as recommended in the corners so can't really make a reliable comparison.
Next is the PiSpeakers 7 Pi cornerhorn. One of the most innovative designs out there, and one of the best high-efficiency speakers as well... especially for the price. Despite the completely different configuration in comparison to the AudioNote, there are sonic similarities: The 7 Pi is likewise a warm and non-fatiguing design. Here's a link to some comments about my first encounter with the 7 Pi:
http://www.audioasylum.com/forums/hug/messages/14/145271.html
Finally, there's the mighty Classic Audio Reproductions Hartsfield. This is an extremely dynamic and lively loudspeaker... in fact, I have not heard its equal in that regard. The first time I heard a pair, I couldn't stop my butt from spontaneously shaking even on music that I didn't particularly like.
Duke
dealer/manufacturer