So, after some more research, without an -LM NIC part, you cannot have AMT functionality, since the coprocessor won't be able to intercept packets from the ethernet interface. It appears to be a specific kind of communication between the ethernet chip and the AMT CPU that cannot be done with a standard NIC. I asked SuperMicro to comment on this, but no response so far. I guess the next stop for me is to interface a raspberry pi with the SMBus/LPC/I2C bus, hardware interface it with the power/reset/power led headers and use it as a BMC/LOM controller. I could even hook up 2 serial ports, redirect the BIOS to one serial port and the OS to another. Or, maybe load google's SGABios OpROM to make sure a serial BIOS interface is possible.