This is more of a reply to Ken Fallon's comments on the Community News than to the original audio.  Ken, the Banana Pi router, with four Ethernet ports, is I believe the only single board solution if you want to build a firewall (though I'm not aware that any of the firewall distros have been ported to ARM.  Ken is right, most of the single board computers (with the exception of ODroid) drive the Ethernet port via the slower USB bus, and the only way to add another Ethernet port is to use a USB adapter anyway.