I know that about 10 years ago, there were these things that were esentially an LCD screen that was placed over an overhead projector and connected to a computer's video out port. These allowed images from the computer to be projected. Now, I have googled around a bit, but have not found any information on them. I know that one can be easily built from a LCD screen, but I do not want to use an expensive LCD monitor for this. The only thing I can think of doing now is taking an old laptop and running it as an X11 terminal to connect to my laptop when I've booted into Debian.