what i have thought of doing was placing hooks on the left and right side of the cab. Then placing dowel rods going from left to right in line with the hooks. could easily tie your line to each dowel and weave it between the lines that are going from left to right in your cab.

Just a thought, I just got my cab built 29" W 36" T 16" D. Sounds pretty close to yours, ill get some pics up once I get the dowels in.