No, not though the tivo. Only some comcast areas can still get on demand though an app on their tivo. It's up to twc to work with tivo to make it a possibility.
But do you really need on demand? With a roamio plus/pro, you'll be able to record what you want without conflicts and won't need on demand.
The only way you would still be able to see on demand is to keep a TWC box and have your tv switch inputs.
Roamio Pro, wired ethernet
Mini using MOCA (from the Pro)
on Cablevision Raritan Valley system (Central NJ)
w/ Cisco PKM803 CableCARD on firmware 126.96.36.1991
*** 2013 newbie to Tivo ***