I'm sure someone has thought of this before but I've never seen it discussed anywhere. I've only seen projectors being used for video effects. John Hyers and AtmosfearFX material comes to mind.
The basic concept here, however, is that projectors can be used to project images onto another surface and then traced onto that surface for other purposes. The obvious application of this would be to project something onto a wall or canvas and then use the image as a basis for a drawing or painting.
I plan to use it for tombstones. My projector can connect to a PC or laptop; if yours doesn't, maybe this won't work or maybe you can dream up something else. Anyway, templates for tombstones are readily available online but the usual method I read is to print out sections onto 8x11 paper and then tape them together to form a single image that you then trace onto a sheet of styrofoam. With a projector, you can project the shape directly onto the sheet, making it as large or small as you want and work from there.
The same goes for epitaphs. Print whatever you want using any desired font and project it onto the tombstone, at any location and any size. This would also apply to things you want to cut out separately and glue onto the tombstone for raised-relief stuff: figures, symbols, lettering, whatever. It takes out the guesswork and having to draw things freehand.
Another thing I might try is black silhouettes cut out of stryofoam or plywood. You could project and cut out some 6 to 8-foot figures without the pain of trying to draw the images yourself. Google the word SILHOUETTE along with words like ZOMBIE, WITCH, SPIDER, MONSTER, GRIM REAPER, etc etc. Paint them black and stand them up off in the distance a little ways, sort of in the shadows but still visible, or with a light behind them . Maybe I'll put eyes on them with L.E.D. lights or reflective tape or black light paint, I haven't really thought it through yet.
Anyway, that's the general idea. If anyone has more ideas or wants to provide a link for further writings about this, they would be most welcome. Cheers.