I am building my personal private cloud. I am considering using second hand dell optiplexes as worker nodes, but they only have 1 NIC and I’d need a contraption like this for my redundant network.
Then this wish came to my mind. Theoretically, such a one box solution could be faster than gigabit too.
Personal Private Cloud then all the money spent on a truly redundant network back-bone is far better spent on just about anything else. Especially if your solution relies on notoriously unrealiable USB nics.
If redundant everything is important then you need to change your planning toward proper rack servers and switches, only way to get a cost effective reliable redundant setup. Use CEPH rather than RAID and ideally, if your workloads are runnable as containers, use a solution that allows you to abstract away the whole server concept as well. Hyper-converged infrastructure is excellent for cost effective setups.