Stu: Thinking of doing the same thing here. I've ripped the guts out of an old VCR before and installed a mini-ITX board, with a DVD drive replacing the tape mechanism. Was thinking of either another mini-ITX or Raspberry pi 3. Connected to an HDHomeRun perhaps?
I did that in about 2004. Except it wasn't mini ITX. Made a great talking point. "Why do you still have a VCR?"