This is interesting, Yamaha and probably a few others have offered "ambience" channels for some time, and I believe the original SACD 5.1 configuration used the .1 channel for an extra pair of high front speakers placed above and just outside the mains insted of for LFE.
I've never heard a set-up like this , but I'd love to. ( It would provide a use for some old Polk satelite speakers that have been collecting dust).
When will outlaw ever get around to releasing the 999 ? If it doesnt beat the 997 to market I may have to buy a Krell something-or-other.