I’ve just completed a few projects where I used the Nikon D800, a 36 megapixel camera as a digital scanner. The ultra high resolution is great as a tool to get the best possible detail of objects.
With a macro lens and extension tubes, I was able to scan 35mm black and white negatives over a lightbox. I then converted the negative images into positives in Lightroom. One of the benefits of this technique is that you get the whole neg with the sprocket holes and a black border. I remember we used to print this way when I was a student – we’d use oversized negative carriers to get this same effect! Sally has posted some of her photography work, with an essay about artist Tony Fomison on her site.
I’ve used a studio setup in the past to photograph artworks in the past. The main challenge with reflective surfaces is to use a polariser on the lens and black out the studio environment. I’ve had to create a black light tent at times for tricky works (especially behind glass).