You might want to have some fun with a "flying spot scanner". I thought that they were just the nuts when I was a teen! It's a natural for analog video. Yea, I'm a little off topic, but I'm easily distracted.
Re the digital TV converter -- you are right, I never signed up for one, but my friend Brian LaGrave stopped by my office earlier this morning on his way to visit a customer and he gave me one unopened in its original box -- I'll report back on ho wit works as soon as I find a moment to try it out (I need to get an antenna first)
Also I LOVE the idea of using it on a Telepresense robot
If you want an "off-the shelf" solution, you might want to look a set-top streaming box like Roku, WDTV Live, or Boxee. My favorite is the WDTV Live because it will stream just about any video format you can throw at it. In addition to the HDMI output it has composite video and audio that you can plug into an inexpensive modulator which will put it on channel 3 or 4 for your TV.