Beyond Compare is awesome and handles this and many other things quite well.

Cool concept.

Proxy/firewall that only lets them talk to the printer?

+1 for “USB Extender over CAT5E or CAT6 Connection up to 150ft” since that keeps the current workflow they seem capable of doing. That’s probably what I would do.

This reads like an nVidia press release.

It is. It doesn’t hide read posts, but that’s the only major thing it’s missing.