It might work with USB drives, but it is not a very neat solution and I was thinking about the Cell based homeservers that were frequently mentioned a couple of years ago.? Sony's location free players don't have much capacity? I can buy a 1 TB portable USB2 drive and that sure seems like enough for DVR.
I guess the card goes into the little box.I would really like to see DVR on PS3 but where would the cable card go?
http://www.hdtvinfo.eu/news/game-consoles/playtv-for-the-ps3-features-2-1080p-tuners.html