Sorry for the poor photo, this is all that survives of a game board I made for a local convention game back in 2000.
Somewhat zoomable version in the gallery:
http://www.dakkadakka.com/gallery/630390-Death%20Star%2C%20X-Wing%2C%20Death%20Star%20Trench%20board.html
It was originally played with the old West End Game Star Warrior rules (a
d6 game).
The board was made from 6 sheets of gray styrofoam board (28" X 32"), with probably another 4-5 styrofoam boards cut into smaller squares and glued on top of the base boards. I made a "death star" surface template in MS publisher, which I photocopied, cut up and glued to the smaller board pieces to give it "texture".
The trench was approximately 4" deep and 6" wide. The bottom of it was made from a gray styrofoam board cut into strips. The walls were made similar to the surface - a base made of long strips like the trench floor with smaller squares cut out and glued with about 1/4" spacing between them. At the end of the trench (not visible in this photo) was a special raised board with the infamous "3-meter exhaust port". If you can zoom in, you can barely make out the wing of a micro machine tie fighter in the trench (if you didn't know, they're about the same exact size as the X-wing game minis).
The tower guns were made from white legos with a tapering trapazoid top made of paper and toothpick guns. There was one gun tower/shield tower made (which is just to the one side of my wife in the picture) and about a dozen smaller guns ("some in the tower, some on the surface").
(And this was about how I felt making it by myself
https://www.youtube.com/watch?v=Zj8PxMAG8rs)