Anyone knows where to by mini 6 pin PCIe to 6 pin PCIe for Mac Pro with GTX 570 ???

Hi,

so I got my new MSI GTX 570 Twin Frozr II and I noticed that the card has two 6 pin PCI power inputs but I only have one power cable from the GT 8800 that came with the Mac.

I think this cable should do it:

However out of curiosity, would a dual cable still work in the MacPro so meaning I run the GT 8800 to drive the display and the GTX to do the CUDA rendering? The GT 8800 gets on 6 pin to 6 pin cable and the GTX 570 gets a 6 pin to dual 6 pin cable?