My sign is affixed to galvanized wire fencing which has 2" x 4" spacings. You can buy it in rolls at home improvement or farm supply stores.
I used MS Word to find a font and layout that I liked. Then I overlayed a grid 2x4 grid scaled to the size I wanted. I transferred the points where the letters cross on the grid to the fencing, and wire tied the rope light at all crossings. Electrical tape covers breaks and extra bits of rope.
Sorry...no pictures of it actually hanging up.