This would have been a waste of time since many cable companies are moving to SDV (Switched Digital Video) to deliver their channels which requires a return path. Plus the guide data varies with each cable operator with some still using the Prevue/Motorola guide or Scientific Atlanta SARA) Microsoft tried this back in the 2000s with Windows Media Center and UltimateTV and failed.
Also, the FFC has recently scrapped the CableCard requirement which is needed to descramble the channels themselves. Many have already dropped support for third-party DVR's like Tivo. This also locks out using TV to descramble the signals, requiring a set-top box to be used.
The old X1 would be obsolete by now as a rental box option for a cable company anyway. It would have been an interesting idea to rent a console with a second hdd and a Cablecard to customers as a Set-top box/DVR/Game Console back in 2013. Cable TV is just about on life-support as it is now, so, a lot less interesting today.