I think that your first idea is cool, although you will need more colors!
I remember that a lot of those ads you mention used color characters so at to provide a "background" to their ansi art. And at least epice megagames also used a black box with text in the middle of all the ansi.
And your idea of modify the exe... I don't like it. Yeah, it could be cool and all but... it will require to mess with the binaries of the game, and the game will be no longer the original game... I know we have some ripped version of games, but that is because of bandwidth... and usually we have the full version in the ISO cellar.
Besides, reverse engineer the game code to do something that it's not required to play the game goes against the ethic of respect copyright, except insofar as to make the game playable and available in the face of the abandonment of it (I hope I have not messed up my english, there).
But, I repeat, I like your first idea... specially if the get it button is just after that or INTO that
... although the last one is not as easy to integrate as the first one.