David,

I use a Visioneer 6100 scanner (less than $150) and the software with
the scanner is sufficient to do most of what you need to get a decent
image (i.e. scanning a dorsal image and then scanning a ventral image
and combining them into a single image with two views of your shell).
There is a lot more you can do with a shell image, but for that you
really need something like Paintshop Pro or similar software.  If you
get a scanner and want some tips, write me off line and I'd be happy to
share what I have learned.  I got similar help from Bill Frank of
Jacksonville Shell Club web page fame.  I can also let you see what the
images from this machine look like.

Tom Eichhorst in New Mexico, USA