When it comes to getting Raspberry Pis into schools, I believe that the biggest hurdle is what monitors (displays/screens) the school has available. Perhaps something like this could be used? It’s a circuit board that outputs VGA, but I’m not sure of the input.
http://pi.gadgetoid.co.uk/post/011-vga-out-on-the-pi

Or perhaps we could get away with a composite video to VGA socket?