It sounds more to me like you just want to put a regular DVD Movie Player in there to feed the TV, would that be correct?

If so: The Memorex DVD Player in the MacintoshClassicIIIColorTVp™ would be my suggestion.

From the info in Ports and Pinouts, it looks like you've limited to a Co-Axial Antenna feed into that thing?

If that's the case, unless you really want to keep it stock, I'd strongly suggest hacking ANYTHING with a TV Tuner setup with the S-Video feed in there. Even a RoadApple PPC with the tuner card would be a huge improvement over that board for just about anything imaginable and you'd get IDE/Silent SD Boot capability as an added bonus.

The cool thing about the Memorex DVD Players is that they have an extra inch of plastic tray up front of the DVD that's just perfect for cutting down fitting about a half to three quarters of an inch of the @$$ end of a cartridge cartridge to, but PLEASE paint it black, the MacTV looks just shy of butt ugly with a beige cartridge stuck in its black maw.

p.s. I'm glad that S-Video out Tuner Box is working out nicely.