I've always been a fan of AsRock partly because they have always been good at supporting ECC memory for AMD processors, even in the consumer systems.
For example says it supports ECC memory, and it has 4 PCIe slots that I can use for the 3 network cards I want to use.
I didn't see any AsRock motherboards with newer chipsets that would have enough PCIe slots though.
Should I consider doing something else?