Right now I am considering cantilevered (floating) shelves; wood, glass, stone or 3/4 inch PVC; with PVC, so far in the lead since it is relatively dead and thus less susceptible to sympathetic vibration. I fully expect to do a quick-survey of the available online shelves before making my own. The shelves will need to be able to conservatively support at least 80 pounds.
At best this question is a bit premature as I do not expect this to be a particularly successful experiment.
I expect to, initially, put a set of speakers on the existing lamp table Midway between the front and rear speakers , along the (Left) long wall and on the other side of the room to place them on the back of the loveseat (Right) .
If I like what I hear; I will likely make up some shelves that appear to float in space and attach them to the wall with some (3/8 or 1/2 inch diameter) steel pins (running deep into the studs).
Everyone needs to bear in mind that all of these plans are, at best, preliminary.
PUBLIC SERVICE Announcement:
These speakers should be considered, IMO, MID-RANGE speakers only and, IMO, are produced to attempt to make flat screen televisions sound LESS BAD.
IMO: they have little to no chance of producing anything close to audiophile quality sound They produce little to no bass (in spite of user ratings and advertising).
The primary purpose of this experiment is to determine what kind of and how much sound is produced by the surround outputs (L and R). And I fully expect to replace these speakers, with something better, over the next year.
PLEASE, folks refrain from purchasing these over priced speakers; the three that I have were obtained mostly by others... And at $400 each much better bookshelf speakers are, probably, available.
Enjoy!