His starting requirements include one pci card for 25gb and another for 4 port 10gb. I don't think there's any low power way to do that. Any motherboard with enough slots, CPU power, and PCI lanes to handle all that aggregate bandwidth isn't going to be low power setup. If you underpowered it, then you might as well back off of 25gb/10gb.

So it's not really a home server. It just happens to be in a home.