I never found one.  The DVR has an esata port, but comcast disables it.  Only way I found was to play the content and feed it to a DVR recorder via the low res outputs.  You can also feed from component or HDMI, but that requires an HD capture card into a PC.  I have never seen an HD enabled recorder, and the folk knowlege is that it is prohibited by the HDCP copy protection specs.