I've tried a few things that can replace a scanner. Let's share.
Since I only use the scanner for sketches and basic character traits, I don't really need that much precision but I do need it to be focused and not distorted.
1) iPhone photos. Crap. iPhone lacks a flash and is completely incapable of applying the right focus.
2) iSight camera from my rusty macbook. So-so, it has a pretend-flash and seems to be better at focusing, but it forces me to hold the paper at just the right distance.
3) Cheap Nikon Coolpix digital camera. Clear winner. Using the 'close-up' mode it seems to be able to focus perfectly on the drawings.
So 3 it is. All this effort is because it seems to be easier for me to outline a sketch using the ancient method of pencil and paper. See this example below, which had a threshold applied to make it black and white.
And I even used a movement line (the curved line that goes from top to bottom) to define the shape of the cat. I'm going pro.