I made a Death Star Trench with the help of some friends for a New Year’s Eve X-wing party. I used foam board and computer printouts for the surface, and cardstock for the turbo laser towers.
The PDF for the Death Star surface is made by Warscapes and cost about $3. You can buy it from RPG Now.
The PDF for the Turbolasers is available for free at http://www.studiokitsune.it
It even folds down into a flat play mat.I put up a separate Imgur gallery with some more photos of its contruction.