Ask, and ye shall recieve! I have more to add...and in a more user-friendly format. If I could (hint, hint) edit my inital post, I would do the same to that.
(Although, it seems you cannot wrap URL tags around image tags...)
I was curious about that video adapter, so I figured, why not throw the 'scope on it, and see what the signal looks like?
So, here we go:
Click HERE for Large Version

A closer look:
Click HERE for Large Version

How about a shutdown screen:
Click HERE for Large Version

At first glance, it doesn't look like anything I recognize, so some more research is in order. It bears a superficial resemblance to a composite signal, but I don't think it is. A mystery for another day...