I'm looking to put together a new computer and I only run Linux on the desktop (latest Kubuntu) I'm planning on a i7 haswell, nvidia 770, 12GB of RAM, SSD. That said, I want a MB that...
is SLI capable
supports 7.1 audio over HDMI or digital optical out
needs to have room for 6 hard drives (at least, I have a RAID5 array for media store and information I don't want to lose)
and at least 3 usb3 ports.

Of course, whatever I buy I want to be 100% linux compatible.

Any recommendations?