I'm looking at getting an X200s with the 1440 screen, and i found one going for relatively little money, but it has a problem with the screen, as shown in the picture below




now, to me it looks like its a problem with the backlight and/or backlight diffusor. would it be relatively simple to correct by a technically inclined person such as myself? or would it require a full panel replacement?

You need a new panel to get rid of all those dark stripes and white spots.
Somebody probably already tried (unsuccessfully I'd say) to swap the CCFL, by the looks of it.