We are having to make a cake to replicate a court and we need to feed 500 people. We need help on the construction of the cake.

Send Doug a pm. He can turn out a sketch for you in minutes. He's awsome with this sort of thing. Good luck.
Amy

What kind of help would you like?

If we could have a few more details, it will be easier to give you more helpful advice.

If your court house is like ours (built in 1880's) it probably is pretty much square, or a cube with a tower on top. If it needs to feed 500, it will be very heavy.

Can you make the walls of the cake ahead of time and then glue them on with royal icing? The main part of the cake will be 6 full sheet cakes stacked on top of each other. We are making the top out of foam. Or do you think that the walls will be to hard to cut through if we did that? Please help.

What are you planning on making the walls from? Gumpaste? Chocolate? Fondant?
If the first two, it would be hard to cut through (but it could be removed before cutting) and the fondant may not stand-up on its own. The fondant probably should cover the entire cake so the weight of the fondant is spread over the top. That is a huge piece of fondant to roll out!
Be sure to have every two layers on cardboards and dowel each so the cake doesn't collapse.