Thanks for all the replies, folks!

It looks like 7.1 is out for me based on workable space around my listening position, but I may try a 6.1 set up.

I recall someone, somewhere mentioning that the pyschoacoustic effect of a single rear surround speaker (i.e. 6.1) is that the center rear effects appear to be happening in front of you, not behind you.

Anyone recall reading or hearing anything about that?