said by cypherstream 
:Sure you could network recorded DVR content that way, but the client cable box in the bedroom or whatever would also need to be connected to the coax to pull one of the oob data addressing channels (our area uses 104.2 MHz). Without this connection the set top box will not download the guide or turn on features such as DVR or MRDVR.
What your looking for is something more like Slingbox. Comcast is trying to implement this using existing cable boxes with little to no modification (therefore costs less). Plus I'm sure they don't mind sending a tech out to relocate an outlet, they do charge $$ for it after all.
If it uses ethernet over any medium it don't need to tune. It's basically iptv 
·
which can carry over anything that can carry an electrical charge really.