Somewhere I think I saw, (SMR or maybe HTF) it does look like DPL IIx supports "stereo" rears.

A couple more thoughts:

If I was Outlaw, I'd see what it would take to do an Eprom (EEprom?) upgrade to the 950, and then charge $50 - 100 for it. If possible.

And then maybe the 950 mk II or the the big brother would presumably include this. (Along with THX Ultra2, although maybe like DD EX vs THX EX, DPL IIx makes THX Ultra2 less "important" as an option.)

And, a final thought, even though as a relatively new owner of an MC-8 (and former owner of the 950), I see DPL IIx as a good thing. If it comes anywhere close to Logic 7, might cause Lexicon to lower its price of admission for Logic 7. I was always surprised that other than the 8000, none of H/K's receivers had it for 5.1 sources. And then personally, I'd wouldn't be surprised to find out it was an accident for the 8000 as well.