I know you have ideas why not look at some of the cinema suppliers in the US, I’m sure they have a few JBL cinema surrounds going on the cheap 8330 and 8340’s.
These days you can pick up the real deal for less if you poke around a bit.
They don’t come with brackets, but are best when mounted flush ageist the walls, THX approved.
http://www.iceco.com/JBL%20Speakers.htm