If im understanding you correctly, the answer is no. That board does shave two pciex16 slots, but with both of them being used, only one will run at full speeds.
That being said, i dont understand why you couldnt use the bottom pciex16 for the vid card, and one of the pcie x1 for the x-fi card. This would fix your problem.
I cant see why the video card would have to be "above" the x-fi card.
Also, is the sound card really neccesary? the board has onboard audio that should support surround sound.