Via the incredibly awesome Propnomicon,
A Zeppelin Goldmine.
High-quality images of blueprints for proposed 100,000 cubic metre zepps from the very early 1920s. For reference, Graf Zeppelin herself, last and greatest of the real-life zepps, was roughly 110,000 cubic metres.
All the images are available in
a Flickr set (use the little grey All Sizes button to get the large versions) and the entire book (a very nice history of the Zeppelin company up to about 1920) is available
in several formats including PDF from the Internet Archives.
That one looks quite buildable as a 28mm "set" in two levels, control cabin and saloon in the lower level gondola, staterooms and such in a slightly larger "2nd storey". Tempting.
Incidentially, even if you're not a Cthulhu RPG player (I'm not, currently), Propnomicon is well worth following. All sorts of creative and awesome things, many of them with uses outside Cthulhu RPG!