Support for ECC RAM tends to be a CPU-designated feature so it's kind of a given when utilizing a 2P board since the E5 product family supports it. Most 2P server grade boards that I've seen take both ECC + buffered or unbuffered DIMM or just standard RAM.
If you need some boards and don't want to wait for the odd Supermicro deal to pop up, the Tyan S7050GM4NR is going for 250 OBO on ebay, seller convertechs-mike. I was able to pick 5 up for 186/ea, new in box, presumably if they have a warranty then it's good for 3 years. It has quad LAN(2 i350 and 2 82574L) + IPMI shared with one of the 82574L ports. Not ideal but whatever. 10 SATA ports, 5 PCIe and 1 PCI. Although, one of the PCIe is a x4 connector, kind of dumb, no higher-ish-end HBA, HCA, or networking adapter is compatible with that slot, so I don't count it really...unless you put an PCIe SSD in it. It also has the 7 PWM fan headers which is perfect, the 836 and 846 chassis I'm using, combined with CPU fans, have exactly that many.
There's a few annoyances though with this board, if you put it in a Supermicro chassis. The CPU power connectors are in more irregular positions, it wouldnt be a problem but Supermicro PDUs are practically catered to their boards. So, in my case I had to cut the ziptie and was able to get enough length from one of the connectors, but, I still had to buy some extensions for the other.
The other thing is the front panel header is at the very bottom of the board. On SM boards it's on the right side, in the middle, ideal for any of their chassis. But in the 836 chassis, the FPIO is on the right side, putting it way on the other side and out of reach. So, I had to buy some of these:
NEW Lot of 5 SuperMicro CBL084L 16-Pin Front Control Split Connector Cable