Looking to upgrade my back surround sound speakers


I am looking to upgrade both my back surround sound speakers as part of my 5.1 setup. I currently have Martin Logan Spire as my L/R and the Martin Logan Encore as my center channel. Any suggestions? Should I keep with the Martin Logan brand...do they make dipole/bipole/monopole speakers?

I have a beam about 10 inches behind the listening area and a wall in which I would mount the rears. I prefer not to dig into the wall and thus prefer mounted speakers.
pig2fever
I just realized that the beam is only 7 inches wide and thus your typical back surround is ~10 inches. So I am now looking into Anthony Gallo speakers. Never really heard of them. What is your opionions?
They make a fine mini monitor and for what your doing it will work fine, just make sure you set correct crossovers as they have very limited low range output.
I'm confused, Pig2fever. Was your question related to side surrounds, 4 & 5 of a 5.1 setup or rear surrounds, 6 & 7 of 7.1 setup? If 4 & 5, and if multi-channel music is important, matching the voicing of the 5 speakers is important. Is there any music that invokes channels 6 & 7 or are those channels used for film effects? Although I've tried to be careful about matching the voicing of the 5 speakers, I'm thinking about in-walls for 6 & 7.

db