I'm surprised that it is a VGA monitor (and by "VGA" I don't mean simply its resolution, I mean the VGA interface as well). The car-TV monitors I've run into have composite or S-video inputs. Osgeld has mentioned seeing ones with RGB and DVI/HDMI inputs, but these would still require non-trivial amounts of hacking to adapt them to a CC (and the CC itself would still have to be upgraded to provide a VGA-compatible output in any case).
And to answer another question, the inner surface of a compact mac's crt bezel is not all in one plane, unfortunately, so mechanical hacking is needed, too.