I've only tested this on bright house so I don't know if it work on any other providers but in theory it should.
You can eliminate the extra cost of the whole house DVR and the headache of some moron bright house tech coming to your house.
You need Two Samsung SMT--H3272 HD-DVR (Supplied by Bright House)
Two Ethernet Cord's
Apple Airport Extreme (I'm sure any spare router will work, this is just the one I had an extra of)
Set up the Air Port Extreme in a central location of the Two TV's you wish to share recordings with.
On the Back of each of the Samsung SMT-H3272 STB are LAN port's run one Ethernet Cord from each of the STB to the back of the air port extreme (or other router, if it works like I said I only tested this with an Airport Extreme)
Re-boot both boxes and check your DVR list, you will have show from each box.
I also am going to try this in the future with an Airport Express when I have the Money to eliminate the hassle of one wire and having to hide an extremely long ethernet cord under a rug.