I've installed the C2G 40697. I had to buy one coaxial to optical converter, but I now have all 6 screens connected to my Onkyo (upgraded to TX-NR708) with digital optical cable and can enjoy 5.1 sound from any of 6 games.
Thanks again for the tips!
Now for some HDMI discussion. I wanted to connect my Panasonic DMP-BDT220 Blu-ray/Mitsubishi LT-40134 display to the Onkyo with HDMI to experience the best possible video and the latest audio formats such as Dolby TrueHD, etc. As explained in the OP, due to the nature of my six screen setup, I did not want the MItsubishi's input source to automatically change when I select various audio outputs from the AVR.
The way I have connected this currently is not according to mfg. instructions. I am inputting only 1 HDMI connection into the Onkyo; the Blu-ray player connected to "BD/DVD" input. The Mitsubishi is connected directly to my cable box via HDMI; it is not running through the receiver. The HDMI output is obviously connected to the Mitsubishi display, but I don't select "TV/CD" as the audio output as the owners' manual insists. Instead I select "BD/DVD."
Thus far I have had to disconnect the HDMI input from the back of the Onkyo once or twice (I believe this is due to the Mitsubishi TV, the Panasonic Blu-ray, and the Onkyo AVR linking together because of CEC rather than the way the pass through is set up, but that's another annoying issue entirely) but otherwise it appears I've somewhat successfully circumvented the system. When I first turn on the Mitsubishi and Blu-ray, my receiver automatically goes to "TV/CD" for audio output. But once I select "BD/DVD," all systems are go from there.
Can anyone comment on this? Have I really "outsmarted" the receiver or am I doing something which will eventually cause some sort of real problem or damage?