"You can also use a macro lens with your DSLR to get decent scans from black and white film."
I was thinking about this for color negatives. if you DLSR an unexposed frame and the image on the same light box at the same exposure the color balance will match. Bring both to Photoshop with the unexposed on top, make a background copy and invert both. Change the mode to color on the unexposed. That should remove the color cast. If needed you can go back to your color mask and make adjustments to optimize the color balance although it will most likely need more work.
I remember having to do this kind of thing with negatives on my first (Agfa) scanner.