Just a couple quick thoughts here.

JJ2 was made in a time when widescreen monitors/displays were not at all common in the mainstream market. As a result, it doesn't support any real widescreen resolutions. I know all too well that modifying JJ2's resolution to something higher than what the game supports doesn't really work (at least, reliably). However, what if there was an option for a widescreen resolution that is lower than 640x480? Personally, I wouldn't mind losing some pixels if the game didn't stretch to fill my widescreen display, which looks rather ugly.