This seems like a potential sweet spot for the Espressobin [1] with pfsense but the pfsense folks have not released their ARM version, only demonstrated it [2], perhaps they're just too dang busy or perhaps it would cut into the margins of their x86 solutions. Regardless it would make a nice appliance if they ever do release a PFsense ARM image.

[1]http://espressobin.net/

[2] https://gist.github.com/gonzopancho/760ab9ecee9dfbc1b6033e48...