I've seen them at garage sales around. You can also get a craft tracer/projector/enlarger like this one:
http://www.enasco.com/product/9729153
BTW, if you do any kind of crafts at all, you need to sign up for the Nasco Craft catalog at the above site!
Also, fleurdelisquilts, I love your avatar. I am currently making a bright + white quilt and was toying with the idea of a applique border, but wasn't sure what it would look like. Yours is FABULOUS!!! I'l have to use my enlarger to make some flowers & leaves.