That story is a bit odd, still -- normally behind the connector there is optionally magnetics, and at least a PHY... being able to integrate the magnetics in the connector exists allright, but adding the phy /as well/ must make it a marvel of integration regular manufacturers would dream of... especially at Gb speed! Also, you can't really 'piggyback' ethernet easily, for the same reasons; you would need TWO phy in t…
Elsewhere in this thread there is an actual link to an actual NSA device that does exactly this. I don't think it's in the realm of science fiction.
Still, if these are in the wild, then perhaps our chinese friends might have reduced the footprint even more to the size of one connector.
I know the connectors with integrated magnetics are quite a bit 'longer' and 'beefier' than the passive ones.