Panhead, if your listening position (couch, chairs...etc) will be placed up against the back wall I don't believe you'll have any issues with mounting the QS8s on the back wall, due to the QS8s being very forgiving regarding placement.
We had the QS8s located on the back wall in our first setup and they sounded great.
If you decide to hang them from the ceiling Axiom offers a
Full Metal Ceiling Bracket and they also offer a an
FMS QS Stand that you may mount the speakers on for placement within the boundaries of the room if you do not want the ceiling mount.
Full Metal Ceiling Bracket...
FMS QS Stand...
