The Z8NA-D6 is the new motherboard from ASUS, and it's not for the faint of heart. It is the first motherboard that has two 1366 sockets, which will enable the user to have 16 virtual cores (8 physical with Hyper-Threading turned off).
There is a catch though; to run this beefy motherboard you will need to use Intel's server processors. It supports Intel's new Xeon 5500 processors as well. This board is not to be sniffed at. Along with support for 48GB of Registered RAM, 24GB of Unbuffered RAM, 1 PCI-E X16 Slot, and 2 PCI-E X8 slots, there's also a nice round number of 14 SATA slots. You'll need a PSU that has a 24+8 pin connector as well.