Even the most hardcore lego fans will be impressed by Anders Søborg's scanner built from a Mindstorm NXT kit. The NXT image scanner can scan and save images as a BMP-file in the NXT's flash memory. Images can be saved in either 24-bit true color, 8-bit color or gray scale.
Wanna make one? Anders' has posted a link to the 227 steps at the bottom of this page.