I think you will be amazed by the QS8's. I still catch my self looking around the room to see where a particular noise came from and it can be startling in a good way.
The 7.1 idea certainly wouldn't hurt to try. I would try it in 5.1 with the QS8's first then hook up the little cubes to see if adds or takes away from the desirable effect. As far as overkill, I think I'm the overkill king so any advice I have may be a little extreme. Honestly, I like to keep my system fairly basic and then add incremental changes.
Anyway, Good luck!
Tom
