Camera flatbed scanner back question/suggestion

I've been reading all the material on the web about using a flatbed scanner as back and one of the problems with using these is that the light inside is annoying to hack away since it's used for calibration (either you have to cover it at an opportune moment or trick/hack the drivers to remove cal).

Has anyone tried or know of anyone who's tried a scanner which supports film/negatives, and presumably uses the "backlight" for calibration and such? Since in the cameras the light from the image would emulate such a backlight, calibration should be much simpler.

Thanks.

note: I actually posted this in the DIY forum first since I didn't see this one which seems more appropriate. Admins please remove/move/merge/whatever the original.