We heard that when the Zeppelin NT prototype was built it didn't have a toilet aboard, leading to a joke about the NT (which actually stands for New Technology) meaning 'no toilet'. Just to reassure our potential passengers, the Zeppelin does have a loo. (good British word there, albeit with a French origin.)
Here are some pictures of the toilet in #3 and one under construction for #4. I have a great picture of the blueprint for the toilet. Perhaps it would make a fun poster..