Aaahhhh!
I've been thinking about this but in a slightly different way. Denon receivers have a mode whereby the left surround info is *also* sent to the left rear, and the right surround info is also sent to the rigth rear. (Sort of another variation on the CES modes.)
But obviously we can't do that with SACD/DVD-A material via the 5.1 inputs. But we can.
I haven't completely written this down schemetically to make sure it would work, but the idea is to create a Y input into each rear channel of the amp. One side of the Y is the normal rear output from the 950, the other side is Y'ed out from the surround channel on the same side. (So I think you'd actually need 4 Y's.) You use one of those Radio Shack line level switcher things. (Some people use these to switch between separate DVD-A and SACD players on the same 5.1 inputs.)
The tricky part is setting levels with the switches in "copy mode". Most likely would be different than "normal" 7.1.
Another thought: ideally in a 7.1 setup, the surrounds are supposedd to be at 90 deg angles from dead center front, i.e., directly to the sides. Personally, I feel this is a better setup for 5.1 music than using the rears, because your ears have a lot easier time hearing stuff to the side than behind you. But obviously, ymmv...
[This message has been edited by Kevin C Brown (edited January 19, 2003).]