Hey tikiman, thats a brilliant idea...
I've tried using your method. I used my monitor as the lightbox, and I used a 1:1 macro lens to take a shot of the slide. I must say that I'm quite impressed by the results!
Here are 2 shots..
Notes: do not place ur film on your monitor, you will see...
Last one from the roll of Velvia 50...
Nikon F4s, 17-35, Velvia 50
Same perspective as the sunrise shot earlier on, cropped to 617 for a better composition :(
I used the auto tone/color/contrast function from photoshop, there was a kind of cold cast to it on the original scan. Forgot to mention that I was using a GND for the last shot too...