I assume it will support 8-channels. You get a limited # of notches, where you use them is up to you. You want to take care of the front speakers first. Then you can use what is left over on the rears.

I estitmate between $2k-$5k for such a card. That is just a number I pulled out of thin air, so take it as a grain of salt.

Again, It is probably going to be a V4 option. (based on CES info 2 years ago. (or was that Cedia? I don't recall.)

Stacey Spears
Co-Creator, Spears & Munsil High Definition Benchmark, Blu-ray Edition and Lighthouses of the Pacific Northwest.