I can't see how eradicating Bose from your home could ever be a bad thing
I'd be sorely tempted to try the single QS8 solution. If you don't like it, you can always send it back.
Another option (especially given that you've got to have the L/R surrounds "behind") might be to get a direct-radiating speaker for the rear channel - like a M2. Rather than bounce signals all around with 3 QS8's, it is possible that a direct radiating rear surround might help "anchor" the surround material better.
There really is no 7.1 source material; depending upon your receiver, it is most likely just the same signal out of both of the rear channels. My understanding is that even the 6th channel is virtually always simply synthesized by the receiver rather than being part of the source. Craig (spiffnme) went from 5.1 to 7.1 and the change did not exactly rock his world.
But really, romy, buddy, you've got an awesome setup. Unceremoneously ditch the Bose.
