Over the years, as a mastering engineer, I have been carring out experimentation with placing symetrical loudspeakers (mirror imaged) on their sides with the tweeters on the inside of the image. I have a lot to say about it but frankly, have you ever considered it and listened to your loudspeakers on their sides for a considerable amount of time?
I will add more to this discussion of my thoughts in about 24 hours or so. One thing I will leave you with is "all drivers are at ear level" in this configuration.
If you have not tried it with your current set-up..by all means go ahead and give it a shot. Make certain that you listen for at least 2 hours in this configuration to get used to it and then report back your findings from an overall SOUND QUALITY perspective.
Looking forward to seeing what others observe.