Strictly for the sake of curiosity, how large of a custom piece could you produce with and without seams (e.g. another commenter asked about creating a custom floor)?
We'd love to make a custom floor! We can do any size piece as long as it's tiled by panels. It'd be cheaper to use the standard sizes (so the largest panel to tile would be 16x20) as it helps us conserve material. But we can conceivably make single maps or panels as large as 18x32, which is the size of our laser-cutter.