I bought one of these things from QVC for my kids. Oh, OK, I bought it for me really, but my kids love it.
I feel there could easily be a market for a more advanced version of the C64DTV where it is placed in a small box with a keyboard, two joystick ports and a flash card slot so that it could be used as a "real" C64 and other programs could be loaded from the card. An additional expansion slot where a module enabling "real" C64 or modern drives to be connected could also be useful.
It would interest people who want more than what the C64DTV has to offer, but who don't want to piddle around building a CommdoreOne.