Hmm, 19v is an awkward voltage! I'd normally recommend something like the "12V Laptop Car Power Supply" on
this page, but I haven't seen one that does 19v. Bit costly too ($70+ from memory).
I have often wanted to try using a TV or similar device plugged in to the camer'as AV, but one thing I keep thinking of is that the resolution of the TV probably isn't up to the task of a sharp focus. Still would be interesting to try.
Another option is a ZigView, better than a TV but not as good as a laptop. But they cost $.
Roger.