Worldwide:
I run a pair of Outlaw's own PCA Y-Adapters ($25ea) from the 950's main L/R outputs. I split the main L/R each into 2 signals and bi-amp my mains using the 770's main L/R + rear surr L/R channels respectively to drive the speakers (which obviously need to be bi-wirable, and able to handle the power).
I figured when I want to go to 7.1 I will either buy a couple 200 monoblocks for the rears or go back to bi-wiring (unlikely now that I have heard the big bottom end and incredible dynamic range of bi-amping).
The PCA Y-Adapters are quite good. I bought them skeptically (considered it a $50 experiment), but noticed little/no voltage loss and no signal degradation.
As a general note, I have been really happy with the PCA interconnects - good construction quality and the locking terminators are great, especially when you have an built-in entertainment center and a 100+lb amplifier that is very hard to get behind.