Thanks, Gus.
My worry is that once you connect the two 12V supplies together; wont they feed back on each other into the MB? Would installing a diode on each supply before connecting them be a better idea? That way the diodes would prevent each of the supplies from back feeding. And I believe the voltage drop would be negligible.
One other thing... I examined my Corsair 850D wiring harness as it includes firewire on the front panel. It's 1394 motherboard header only connects to one of the 12V pins, the other is not connected, yet the port is fully functional.
Your thoughts?