That would be the two InHD channels (InHD) discussed extensively over at avsforum.com. They look like they are trying to be the cable company consortium's answer to HDNet.
What does Comcast Digital cable look like on a projection TV?? Roughly between 47 and 51 inches. I have a 36" Wega right now, and WOW looks really good. I'm worried if I watch Comcast cable on a projection screen, it will look terrible comparitavely.