You will need leather or some fake stuff for the bag. I included a pattern for small 280mm and large 380mm. I used contact cement to hold it all together. The bellows flange will also work with normal bellows but I didn't include a pattern for this.
The small gives a max of 80mm from front to rear standard. You could stack multiple bags. glue them together. Each gives about 80mm. I have not tried the 380mm size yet. I'm guessing maybe 120mm max.
The author marked this model as their own original creation.