Alright, so I want to speculate something based on all the other products that are out there from Hak5 already. Here's what we know.
-- The device uses wired ethernet, but NOT wireless data
-- The device is made for man in the middle attacks
-- The device deals with packets
I think the Packet Squirrel is a three port, 1 gig switch device. One port is an input, one is a clean output, and one is a modified output.
This would be able to process the input and output at really high speed, probably with it's own high-end processor and linux distro to deal with the dataload,