REALLY Persistent Ethernet Interfaces on Linux

So Linux has adopted Persistent Device Naming, which is a really great thing for most systems. Unlike the old days where we just had eth0 and eth1 and eth2 etc (which at least has no spaces unlike Local Area Connection 6 that another OS uses), whose order depended on driver initialization in the kernel. Most people just had eth0 and were happy, and most people will still just have one Ethernet interface and will still be happy.