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I'm a tech for Comcast myself up here in Seattle.
I've seen a few of those tv's in my time, mostly on Mercer Island, and it was usually when the customer had called in about issue's with their service. And they would describe exactly what you were talking about, but they would contribute it to the companies service. But yes, those cable cards have been the bane of many a tech. They are extremely finicky and time consuming to set up, and if anything ever upset them, it was like pulling teeth to get them to work again.
While they were a good idea, the industry has been moving away from them due to a newer model that should be coming out soon. Tru2way (still being tested by CableLabs). These will allow two way communication for video on demand, on screen program guide, etc.
So in the mean time, your options are renting one, using a hardware device in a PC that uses the cablecards, or waiting and using Hulu and other services. But I will tell you the anyroom dvr system is pretty slick and X2 (Comcast's cloud DVR) should be rolling out soonish.
The reason that the days of the free cable boxes are long gone are thanks to the directtv/dish folks. When they were babies (this is what I have heard), they sued the cable industry and the FCC forced the companies to charge a fee for boxes since the satallite systems were not in a position to give "free" equipment.