I made my own. They're ugly but they're free, they're mine, and they're totally custom.
(1) Take the cardboard backing from three or four pads of graph paper. It's best if it's not three-hole punched, and if all the pads are the same size/brand, but if you're careful you can also use mismatched panels.
(2) Lay it side by side in your preferred arrangement with about 1/16 inch between panels, and making sure the bottom edges are straight. The gap between panels is necessary to allow it to flex at the joints.
(3) Tape together with scotch tape or clear packing tape, being sure to preserve the gap.
(4) Flip over, tape the other side.
(5) Stand up, make sure it sits flat on the table. Make sure it is flexible, so you can arrange it as desired without stiffness, springiness, or binding. Also make sure it folds nicely for storage. If anything needs adjustment, cut the offending joint(s) and re-tape.
(6) For durability, wrap a strip of scotch tape around each untaped edge. [optional]
(7) Tape your favorite tables/pictures to the panels. I use MS Word to make custom single-sheet panels with all my favorite data and house rules on them. If you are careful to only attach tape to tape, it is easily removed, allowing the screen to be updated. You can also tape on multiple sheets along the top edges if you like the Hackmaster "flip screen" style.
You can easily make this as big as desired. Want a twenty-panel full-circle "cockpit"? No problem! I have made screens in both "portrait" and "landscape" versions -- landscape is nice because it's low enough to reach over easily to arrange miniatures or draw maps.