Wow the German site asks you to measure your foot with a paper, pencil and a ruler. Although ShoeFitr must already have your shoe in their database, the huge win is there's nothing asked of the user besides what shoe they already like and you can find it from brand name and colors.
But it's possible to solve the other use case. 3D-foot-scanners are already out there for shoemakers, so taking measurements could become easier in the future.
http://www.mirapodo.de/groessen-kompass
I've been working on a similar concept for dress shoes.
http://sizeadvisors.com/