The DSLR+adapter solution does sound more convincing to me, with the right lens, right sensor and settings. Correcting distortions should be a tractable.
One problem with many flatbed scanners (not all of them and not the film scanners) is that they illuminate the film/object from the same side as the sensor, so the light has to travel and bounce more, creating more chances of stray light.
One problem with many flatbed scanners (not all of them and not the film scanners) is that they illuminate the film/object from the same side as the sensor, so the light has to travel and bounce more, creating more chances of stray light.