Hey sushi;
Actually in my post above I did mention that I could NOT compare apples to apples since Axiom is the only quadpole speaker. Everything else was dipole/bipole. But some that came to mind when I demoed.
http://monitoraudiousa.com/products/silver/index.html - Monitor Audio FXi had somewhat the same tonal characteristics as the QS8. Not as dispersed though.
Another was
http://revelspeakers.com/products/overview.asp?ID=11 Revel Performa S30
For dispersion like the QS8 is the Magnepan MGMC1
http://magnepan.com This is effectively a dipole.
Dipoles because the lower frequencies reproduced by the woofers are not particularly directional so it seems to radiate diffusely. A bipole speaker creates a wider soundfield by pushing air out of both sides at the same time. This means that it can be placed pretty much anywhere you wish. (Somebody check this. I might be wring)
Here are other interesting designs:
http://www.mksound.com/ss150.html
