Brian, how about this...Instead of printing my signs on paper, print them on the clear sheets teachers use for overhead projectors.heh heh.... funny how a long thread gets convoluted. We talked about this over a month ago, when you and I were bantering about logo fonts.
I still haven't done anything with backlighting, as I've got three other woodworking priorities. I was considering using a piece of x-mas lights, mounted inside a shadowbox-style frame, with a thin sheet of opaque plexiglass behind the transparency. Should cost no more than $10.