Ya, that board looks pretty sweet. Not sure though how much performance would be gained with quad 16X speeds slots PCI-E 3.0 with the PLX chips versus native quad-8x PCI-E 3.0 with the Rampage IV Extreme.
I had hopes for the ASRock Z77 Extreme9 supporting Quad-crossfire at quad-8x PCI-E 3.0 because of a PLX chip but seeing this new picture I have my doubts (cover says 3-way SLI):
http://img15.imageshack.us/img15/882/z77extreme9.jpg
It seems nVidia will never allow Quad-SLI on anything but X79 this year.
So I basically have two options, go with the R4E which is a known quantity and good board with quad native 8x PCI-E 3.0 or wait for this ASRock Extreme11 which has quad-16x PCI-E 3.0 with PLX chips that add unknown latency and performance.