I can't find a plugin for something like a 2-way mirror. i think that would be nice. Not sure if its possible, but maybe with a command with radius or whatnot, makes a certain block take on the properties of glass when placed, but you can only see through it the way its placed. i.e if you're below it, and you place it as the roof, you can only see up, and here's a kicker, if possible, for the people trying to look in, the 'glass' blocks mimic adjacent blocks. so it looks like one solid block. and i think this is a sketchy idea, but anything along the 'see out not in' idea would be great. i know you can to this with paints and fence, but its unpredictable and has many limits.
I'm not 100% sure but I think that anything that changes how blocks display requires a client side mod, making it very impractical.
Yea sorry but this isnt possible http://forums.bukkit.org/threads/read-me-first-plugin-requests-guide.81209/ read then maybe fix your post up
