Fast forward fifteen years and a couple of quantum leaps in home video technology and those kinds of devices are long-ago extinct.
The Digital Millennium Copyright Act of 1998 has a lot to do with the demise of devices like you describe. As part of getting the certifications that are needed in a modern device (primarily the need that it support HDMI output), there are some show-stopping restrictions with what they can do in terms of analog I/O. Modern DVRs don't have analog inputs. This is why I recommended a computer capture device that does nothing but capture composite (or component) inputs. To my knowledge, there aren't any current (or even recently discontinued) capture devices that offer more than one composite input.
That said, just because a device has the right connectors, doesn't mean it will work for a particular purpose. Many analog capture devices are confounded by even lightweight copy protection schemes.
As I said, that ship has sailed.