Well, well. Looky here. Gigabyte's server division has developed a microATX board with a 64-bit ARM processor onboard.
The datacenter-oriented MP30-AR0 is built around Applied Micro's X-Gene 1 SoC, an eight-core chip with a 2.4GHz clock speed and 45W TDP. The CPU cores are Applied Micro's own design, and they're compatible with the 64-bit ARMv8 ISA. You can read more about the chip's architecture in Scott's article on ARM's push into servers.
This particular implementation pairs the SoC's quad-channel memory controller with eight UDIMM slots. Each slot can take modules up to 16GB and 1600MHz. ECC is supported, of course.
Although the integrated graphics is nothing special, the networking payload is pretty impressive. The board taps into dual 10-Gigabit Ethernet controllers housed in the SoC. Gigabyte adds a couple of auxiliary GigE chips on top of that, both from Marvell.
Storage is limited to four SATA 6Gbps ports and one SD slot. Dual PCIe x16 slots provide a path to expansion, though. Each slot has eight lanes of Gen3 bandwidth, presumably direct from the SoC. There's no mention of lane sharing on the product page.