If I find a cheap LCD at a garage sale, I'd put it on its back and see what the heat does. Possibly start adding a fan to the underside, and/or a screen cover (thin Plexiglas). Having it elevated on pop cans over the table would be nice so people could have their space for books, but then viewing angle would become an issue (if it isn't already).
[Edit: just noticed Jara's post above mine. It looks like viewing angle would rule out a cheap LCD find and would need something special. They have PC screen covers to reduce viewing angle, I wonder if a cover could be added to broaden it.]
For those that have the Projector. How many lumen do you need, and I'm wondering if that's any cheaper than the LCD. How dark do you keep the room (how do you read your character sheet) ?