My wife just got me the C57-D (apparently often mis-labelled "C-57D") space cruiser, the spaceship from the awesome classic SF film,
Forbidden Planet.
It's 710mm in diameter (28 inches) !!! with a nice interior. I thought it was trouble building 900 and 1300mm subs, but at least they are skinny! This won't fit on the workbench! I've got to finish off the Graf Zeppelin so I've got some time to think about it...