The list of supported resolutions is indeed only useful on full-screen
mode...

So, what could be done is to display a list combining some predefined
resolutions + the supported ones, and somehow 'mark' (specific color ?)
the supported ones, so that the player knows which one he can choose in
full-screen mode.

Now, there is still the problem of big lists. I would be in favor of
re-using the keychart code (display several columns)...