With a $1000-ish budget, there are quite a few options
I'm assuming you like and want to keep the more diffuse surround field produced by a bi-pole or di-pole surround speaker. The QS8 are a unique "quad-pole", but since all the drivers in the QS8 fire in phase, they are closest to a bi-pole speaker just in terms of the overall sound.
Revel has their
S12 Surround speaker that retail for just under $1000/pair and can be found for a fair bit less if you search around. The S12 are a very adjustable surround speaker, letting you choose di-pole, bi-pole or dual mono-pole output. The dual mono-pole literally has you connecting two separate speaker wires for two separate channels, effectively making the S12 two separate speakers playing in the same cabinet. They're quite large, but have a nice, clean, curved front face with the grills on that blends easily into any wall. They kinda look like a wall sconce
Focal offers the
Chorus SR 800 V for $1200 retail, but you can find them for less. The SR 800 V are strictly a bi-pole speaker, no options for any other output pattern. Again, they're fairly large, but they have a very attractive look, IMO, with a sort of pointed curve with the grill on. These are quite thin speakers at just about 7 inches deep, so they lay flatter on the wall than a lot of other diffuse surrounds.
Paradigm offers a lot of
diffuse surround speakers . The Monitor Surround 3 at $800/pair are probably your best bet in terms of your target price, good looks and a similar level of sound quality to your QS8 since they use similar drivers and materials. The Surround 3 are strictly a bi-pole design. A very nice, smooth half-cylinder shape makes them one of the sleekest-looking options.
EMP Tek has their inexpensive $500/pair
E55Wi bi-pole surrounds if you'd prefer more of a wedge shape, a glossy finish and a color option other than black
And Aperion Audio offers something similar, but with the option to run them as either bi-pole or di-pole in their $600/pair
Verus Surround , which aren't as big as they look in the pictures. They're actually one of the smaller options listed here.
That should get you started, I think